Corporate Social Responsibility and Human Resource Management: Towards Sustainable Business Organizations

: Today’s organizations are immersed in a global market, where any detail can provide a competitive advantage over rival companies and condition their sustainability. Corporate Social Responsibility and Human Resource Management have become very powerful tools within companies. However, the potential, development, and measurement of Corporate Social Responsibility (CSR) and Human Resource Management (HRM) have not been su ﬃ ciently explored. The literature has developed multiple case studies on CSR and HRM and has studied the combination of both factors and their link to economic, environmental, and social sustainability, but has not yet found a solid basis from which to address the new functionality of CSR, HRM, and sustainable business management. This work aims to investigate trends in scientiﬁc production related to Corporate Social Responsibility and Human Resource Management. Bibliometric techniques and SciMAT software have been used for this purpose. A total of 314 articles from Web of Science (WOS) indexed journals were analyzed. The results obtained conﬁrm that the interest in the study of these concepts has grown exponentially in the last decade. It should be noted that the deﬁnitions of CSR and HRM, and even the relationship between the two, continue to be subject to multiple interpretations. The contribution of this work lies in the fact that, through the longitudinal analysis carried out, light is shed on the groups of issues that emerge with special projection, such as green-management, stakeholders, commitment, competitive-advantage, satisfaction, performance, sustainability, or research-methods-analysis, and which must continue to be explored in order to respond to the demands that business organizations have in this respect, and to help the total integration of the di ﬀ erent approaches related to CSR and HRM. keywords, the research focused on how the literature has evolved in relation to CSR and HRM as seen in Figure 4.


Introduction
Research on Corporate Social Responsibility (CSR) and Human Resource Management (HRM) has experienced an unprecedented boom in the last decade. This increase has not only come from researchers and academics, and the business world has also taken a deep interest in this field [1].
In the literature analyzed, there is no consensus on a definition of CSR [2,3]. In fact, it can be said that CSR is indeterminate, dimensionless, regional, and cultural. The CSR has different meanings depending on where we are, the person interpreting it, or even the company practicing it [4]. The concept of CSR has developed over time [5], and varies by country and cultural background [6]. In fact, Dahlsrud in 2008 [7] published a review article where he brought together 37 different definitions of CSR, concluding that although there is some agreement regarding the identification of the dimensions of CSR, which would be: social, economic, and environmental, it is difficult to develop an impartial and global vision of CSR, mainly due to the specific factors of the context and how each company

Methods
The aim of this work is to understand the trends in scientific production on Corporate Social Responsibility and Human Resources Management. The proposed research is based on the bibliometric analysis of the scientific literature using the article as the basic unit. A bibliometric analysis examines bibliographic material from an objective and quantitative perspective that is useful for organizing information within a field specification [36]; therefore, a metric analysis of the literature allows for the analysis of the details of the main research topics within a domain and the relationships at the micro level, generating useful information for researchers evaluating the scientific activity [37,38].
In the process of analysis, a detailed detail will be made in two differentiated sets-activity indicators and relationship indicators. The observation and study of the selected articles will reveal the evolution of research related to CSR and HRM. Likewise, the information extracted from the literature, such as the year of publication of the articles, authors, citations, origin, impact indices, and other characteristics will allow us to make a complete outline of what scientific production in this field has meant.

Materials
The analysis of publications has been carried out in the Web of Science database in October 2019 [39]. The analysis was carried out in the Web of Science database for two main reasons. The journals indexed in the Web of Science database present one of the highest quality standards of current scientific production. On the other hand, documents from other databases could have been included, but this poses a methodological drawback for some phases of our research. Impact indices and other metrics often differ between the various databases, so a comparison between articles from different sources may generate errors of appreciation. We believe that focusing on a single database, such as Web of Science, provides quality data and information for conducting research of this type. As for the adjustment of the research criteria, the combined expressions "Corporate Social Responsibility" or "CSR" and "Human Resource Management" or "HRM" or "Socially Responsible Human Resources Management" or "SR-HRM" have been used as search parameters. It has been restricted to the Science Citation Index Expanded (SCI-EXPANDED) and Social Sciences Citation Index (SSCI). In both cases the year of publication is not limited. The interest of the research is to find coincidences in articles on CSR and HRM, in the title as well as in the abstract and the keywords of the articles available in the database. "SR-HRM" was included in the search, in order to also include those documents analyzing human resources management from a socially responsible perspective as a result of the permeability of CSR application in organizations. On the other hand, due to the multidisciplinary approach given to this subject, the search has not been restricted to the different categories arranged in the Web of Science (WOS) database.
The configuration described above selected a total of 336 items in this source. To identify the most relevant research, in order to apply a first filter on relevance to the subject matter, the two authors independently read the titles and abstracts of the 336 articles. Both authors agreed on the qualification "suitable" for a total of 302 articles. The 34 articles that did not pass the first review were analyzed further, and it was concluded that 22 of them were not suitable for this bibliometric analysis. Therefore, a total of 314 items were selected. In the analysis of publications using bibliometric techniques, it is usual to select the most cited articles from the entire sample obtained. In this case, it was decided to include the 314 articles that met the search parameters. This means that recent documents that may not yet have reached their full impact are not discarded.
In order to obtain a global and temporal perspective of the evolution of the subject, on the one hand a descriptive statistical analysis was carried out where the indicators of activity of the literature are detailed, and on the other hand, to know the state of the research and its evolution, longitudinal and strategic maps and thematic networks were constructed.
In order to study research on a subject in a longitudinal way, it is necessary to create periods that can contain the set of publications to be analyzed. For this work, the criterion taken has been a compromise between the length of the period and the number of publications. In this sense, it was estimated that periods of 5 years would favor the analysis. The distribution has been done starting from the year of the last document published (2019) backwards; however, due to the low production of publications between 2009 and 1993, it was decided to create a single block containing the set of documents between those dates. The distribution, therefore, was in three periods and as follows: 1993-2009, 2010-2014, and 2015-2019.

Software
The research was supported by the computer tool SciMAT. This software was developed by SECABA, a research group from the University of Granada (Cobo, López-Herrera, Herrera-Viedma, and Herrera, 2012) [40]. SciMAT allows the construction of longitudinal and strategic maps and thematic networks that allow one to see in a chronological way what was the thematic evolution of the literature under study. The following configuration of SciMAT has been carried out for the analysis: the author's keywords and the keywords from the source were used as the unit of analysis, and the co-occurrences were used to build the networks. The equivalence index was used as a measure of similarity to normalize the network, and a single center-clustering algorithm was used to create the scientific map of topics and their networks.
A strategy map is divided into four quadrants ( Figure 1). The motor themes are in the upper right quadrant, the peripheral themes are in the upper left quadrant, the emerging themes are in the lower left quadrant, and the basic themes are in the lower right quadrant [40]. With respect to the former, they represent the motor themes of the specialty, because they present a strong centrality and a high density and they are well developed and are important for the construction of the scientific field; on the other hand, they are very externally related to concepts applicable to other themes. With regard to peripheral issues, they have well-developed internal links, are highly specialized, and are of marginal importance in the scientific field. Emerging or decadent themes have a very low density and centrality and are therefore very underdeveloped and marginal. Finally, the basic themes are important for the scientific field, but they are not sufficiently developed and are cross-cutting and generic themes. Therefore, they are basic themes of the scientific field. The third dimension in the strategic map is included through the theme spheres, where its volume can represent different bibliometric indicators, such as the number of documents associated with a theme, the number of citations received by the documents associated with each theme, or the H-Index of the theme.
From each cluster or main theme, a network is formed which is called a thematic network ( Figure 1). This is formed through the interconnection of keywords based on the documents associated with each theme. Each thematic network is assigned the documents that share some keywords with the network. Two types of networks can be considered: main documents and secondary documents. A main document will be one that contains at least two keywords from the thematic network, and a secondary document will be a document that has at least one keyword associated with the thematic network, so that both primary and secondary documents can belong to more than one thematic network [41]. In this work, both quantitative (documents) and qualitative (H-index) analyses were carried out on the network of primary documents.
Sustainability 2020, 12, x FOR PEER REVIEW 5 of 25 each theme. Each thematic network is assigned the documents that share some keywords with the network. Two types of networks can be considered: main documents and secondary documents. A main document will be one that contains at least two keywords from the thematic network, and a secondary document will be a document that has at least one keyword associated with the thematic network, so that both primary and secondary documents can belong to more than one thematic network [41]. In this work, both quantitative (documents) and qualitative (H-index) analyses were carried out on the network of primary documents.

Activity Indicators in the CSR and HRM Literature
The number of annual publications linking CSR and HRM has increased significantly. The sample analyzed consists of 314 articles, the first of which appeared in 1993, "Corporate socialresponsibility and worker skills-an examination of corporate responses to work place illiteracy contract" published by Anderson in the Journal of Business Ethics [42], where it is shown how corporate philosophies were almost independent of organizational variables. The first research of relevance due to the number of citations it has (270), is that carried out by Albinger and Freeman in 2000 [43], also published in the Journal of Business Ethics. This journal is one of the pioneers and remains the most productive in this field, contributing 38 articles to our collection, with an almost uninterrupted rhythm since 2000.
As can be seen in Figure 2, from 2007 onwards the scientific production related to CSR and HRM started a constant increase, reaching more than 60 articles in 2019. Based on the temporal distribution described in the methodology used in this study, we analyze the literature from the first period (1993-2009), which is characterized by approaches more closely related to business ethics [42,44], and where CSR is beginning to be addressed by researchers through analysis and case studies [45][46][47]. In this period, the connection between CSR and HRM has not yet been strongly developed, although important research has appeared that asks what effect responsible/sustainable management of the company has on human resources and vice versa [48][49][50][51][52][53]. The second period (2010-2014) describes

Activity Indicators in the CSR and HRM Literature
The number of annual publications linking CSR and HRM has increased significantly. The sample analyzed consists of 314 articles, the first of which appeared in 1993, "Corporate social-responsibility and worker skills-an examination of corporate responses to work place illiteracy contract" published by Anderson in the Journal of Business Ethics [42], where it is shown how corporate philosophies were almost independent of organizational variables. The first research of relevance due to the number of citations it has (270), is that carried out by Albinger and Freeman in 2000 [43], also published in the Journal of Business Ethics. This journal is one of the pioneers and remains the most productive in this field, contributing 38 articles to our collection, with an almost uninterrupted rhythm since 2000.
As can be seen in Figure 2, from 2007 onwards the scientific production related to CSR and HRM started a constant increase, reaching more than 60 articles in 2019. Based on the temporal distribution described in the methodology used in this study, we analyze the literature from the first period (1993-2009), which is characterized by approaches more closely related to business ethics [42,44], and where CSR is beginning to be addressed by researchers through analysis and case studies [45][46][47]. In this period, the connection between CSR and HRM has not yet been strongly developed, although important research has appeared that asks what effect responsible/sustainable management of the company has on human resources and vice versa [48][49][50][51][52][53]. The second period (2010-2014) describes an uneven growth in CSR and HRM publications, although in five years the number of publications has increased from 6 to 22 per year. In this second stage we find the first manuscripts that relate CSR to HRM and the organization's business performance [27,[54][55][56][57][58][59]. The third period (2015-2019) presents the highest growth of the studied sample. Out of 20 articles registered in 2015, 62 were registered in 2019, a year that has not yet ended at the time of writing.
The issues addressed during this very productive period are multiple, although certain key terms appear: green management; the impact on companies of CSR practices, where methods of analysis are sought to measure performance; and the impact of CSR and HRM on employees and other stakeholders. Research deals with how to generate the right balance between economic, social, and environmental objectives in an organization [60][61][62][63][64][65], the importance of internal and external stakeholders [66][67][68], green management of human resources [65,[69][70][71][72][73], or how to adequately measure the impact of CSR, HRM, and sustainability on business practices and the company's image [74][75][76][77][78][79]. The issues addressed during this very productive period are multiple, although certain key terms appear: green management; the impact on companies of CSR practices, where methods of analysis are sought to measure performance; and the impact of CSR and HRM on employees and other stakeholders. Research deals with how to generate the right balance between economic, social, and environmental objectives in an organization [60][61][62][63][64][65], the importance of internal and external stakeholders [66][67][68], green management of human resources [65,[69][70][71][72][73], or how to adequately measure the impact of CSR, HRM, and sustainability on business practices and the company's image [74][75][76][77][78][79]. Of the 314 articles analyzed, if we take into account the affiliation of the first author of the chosen research, researchers from the United States of America are the ones that publish the most on this subject with 53 articles, followed by researchers from Spain with 35, China with 29, Australia with 23, and England with 21 (these are the ones that exceed twenty). They are followed by Italy (13), France (11), Germany (11), Canada (10), and Poland (10). The rest of the articles analyzed are distributed among 42 other countries.
In the compilation and counting of articles per author, there are groups of researchers who have jointly published a high number of articles, although the research production with respect to this subject is quite distributed. In total, the 314 articles in the selected sample include 775 authors from 52 countries. The Web of Science (WOS) database scores and publishes the Hirsch Index, or H-index, of each author, which corresponds to the number of publications and the times he or she has been cited. The following table shows the authors with the highest number of publications and their Hindex (Table 1).

Number of Articles
Year Of the 314 articles analyzed, if we take into account the affiliation of the first author of the chosen research, researchers from the United States of America are the ones that publish the most on this subject with 53 articles, followed by researchers from Spain with 35, China with 29, Australia with 23, and England with 21 (these are the ones that exceed twenty). They are followed by Italy (13), France (11), Germany (11), Canada (10), and Poland (10). The rest of the articles analyzed are distributed among 42 other countries.
In the compilation and counting of articles per author, there are groups of researchers who have jointly published a high number of articles, although the research production with respect to this subject is quite distributed. In total, the 314 articles in the selected sample include 775 authors from 52 countries. The Web of Science (WOS) database scores and publishes the Hirsch Index, or H-index, of each author, which corresponds to the number of publications and the times he or she has been cited. The following table shows the authors with the highest number of publications and their H-index (Table 1). The most frequently cited authors per article are not represented in the above list, as their production in this field has not been as numerous, although it has been referenced on many occasions. Fulmer and Gelfand [80] with the manuscript "At What Level (and in Whom) We Trust: Trust Across Multiple Organizational Levels" cited on 475 occasions; and the research of De Stefano, Bagdadli, and Camuffo [10], who presented in 2018 "The HR role in corporate social responsibility and sustainability: A boundary-shifting literature review" with 218 citations.
With respect to the journals with the greatest presence in CSR and HRM research, it can be seen that the set of 314 articles studied in this work from 1993 to 2019 are distributed in 122 different journals, highlighting the Journal of Business Ethics with 38 publications and Sustainability with 30 published researches.
The Impact Factor percentile of the main journals in this bibliometric is usually located in the first and second quartiles. Table 2 lists the journals with the greatest impact on CSR and HRM studies. The WOS database has been analyzed through its Science Citation Index Expanded (SCI-EXPANDED) and Social Sciences Citation Index (SSCI) families, where the quartiles are shown with respect to the rest of the publications in each thematic category and each database. There are cases where some journals present a different classification according to different areas of knowledge, in this case the one corresponding to the subject matter at hand has been chosen. The Journal of Business Ethics, whose volume 1 appeared in 1980, is the most active in this field with 38 articles since 1993, and with a continuous production until these days. The second publication with 30 articles is Sustainability, which appeared in 2009. In Table 3, and using the same numbering and order as Table 2, we show again the journals that have at least 4 publications within the selection made in this article and their activity by year. Table 3. Annual journal activity in articles on CSR and HRM. Darker background color means more journal activity in this area. The Journal of Business Ethics and Sustainability publications represent more than 20% of the articles in the sample. The rest of the journals do not have a large number of works on this subject, which indicates that few journals have specialized specifically in this area. It also gives an idea of how this subject is represented from multidisciplinary approaches and that, although the search in certain areas of knowledge is limited, the study of the CSR and the HRM admits points of view from various disciplines.

Evolution of Keywords
In order to analyze the conceptual and thematic evolution of the literature related to CSR and HRM, we first analyze how keywords have evolved, their overlapping, continuity and discontinuity in a chronological way, taking into account the previously delimited periods. As defined in the methodology, a compromise between the length of the period and the number of publications was used for the delimitation of the periods. However, due to the fact that in recent years the growth of literature on this subject has been so high, the number of documents from this last period is very high, leaving the distribution in terms of documents unbalanced, which has had to be subjected to the necessary weighting filters which the software provides, and which will allow a rigorous analysis to be made. Thus, the first period (1993-2009) contains 24 documents, the second (2010-2014) 78 documents, and the last (2015-2019) 212 documents (Table 4). For the analysis of the evolution of keywords in the area we use the methodology of Price and Gürsey [81]. The circles constitute the established periods and inside them they include the number of keywords of the period. The arrows between periods represent the shared keywords and, in brackets, the stability index or overlap fraction. On the other hand, in each period, the incoming and outgoing arrows report the new keywords and the keywords that have not been used in the following period respectively. Thus we can see in Figure 3 how in each period new keywords are incorporated and others are not used in the next period. A high number of keywords was observed, which gives an idea of the diversity of adjacent topics dealt with by the central core of this study. However, the stability index remained between 0.51 and 0.57, which shows a high and growing strengthening of vocabulary by the scientific community when describing the published documents [40]. As for the analysis of the periods, the number of keywords is closely related to the number of publications, so the last period (2015-2019) accumulates the maximum number of keywords with 582.
Sustainability 2020, 12, x FOR PEER REVIEW 9 of 25 period respectively. Thus we can see in Figure 3 how in each period new keywords are incorporated and others are not used in the next period. A high number of keywords was observed, which gives an idea of the diversity of adjacent topics dealt with by the central core of this study. However, the stability index remained between 0.51 and 0.57, which shows a high and growing strengthening of vocabulary by the scientific community when describing the published documents [40]. As for the analysis of the periods, the number of keywords is closely related to the number of publications, so the last period (2015-2019) accumulates the maximum number of keywords with 582.

Longitudinal Analysis
After analyzing the progress of keywords, the research focused on how the literature has evolved in relation to CSR and HRM as seen in Figure 4.

Period 1993-2009
In this period, taking into account its centrality, the predominant theme is Business-Ethics. This is a driving issue that becomes less relevant in subsequent periods in favor of CSR, which will take the lead in terms of centrality and density until 2019 ( Figure 4). Business-Ethics, with an H-Index of 13, has a relatively low number of documents (16) compared to CSR (77 and 206, first and second periods, respectively). However, although it has the benefit of time, its number of citations (1024) compared to CSR (3277 and 1540, first and second periods, respectively) is relevant and favorable proportionally (Tables 5-7). The most frequently cited works on this subject are published in the Journal of Business Ethics by the authors Albinger and Freeman (2000) [43]; Collins (2000) [82]; Cornelius, Todres, Janjuha-Jivraj, Woods, and Wallace (2008) [83]; and Holder-Webb, Cohen, Nath, and Wood (2009) [84], with a cumulative 670 citations (65.4% of the total). The existence of a positive relationship between employers performing CSR and the capacity to attract more qualified employees, as well as the impact of the size and typology of the companies for the implementation of CSR policies within them, are some of the issues investigated.
As for Business, it occupies a central position in the matrix of the strategic map, which means that it has an equidistant centrality and density; therefore, it is difficult to glimpse the projection of such a theme. The number of papers is 7, with a total of 343 citations and an H-Index of 7. The most cited authors in this area are Vuontisjarvi (2006) [47] and Bohdanowicz and Zientara (2008) [85], 99 and 83 citations, respectively. In the case of the first paper, it deals with the first steps of the CSR in Finland, demonstrating the lack of awareness and information about it. The second publication is a case study of CSR in hospitality companies, highlighting the implications of CSR for human resource management and support for local communities and the promotion of environmental sustainability.

Longitudinal Analysis
After analyzing the progress of keywords, the research focused on how the literature has evolved in relation to CSR and HRM as seen in Figure 4.

Period 1993-2009
In this period, taking into account its centrality, the predominant theme is Business-Ethics. This is a driving issue that becomes less relevant in subsequent periods in favor of CSR, which will take the lead in terms of centrality and density until 2019 ( Figure 4). Business-Ethics, with an H-Index of 13, has a relatively low number of documents (16) compared to CSR (77 and 206, first and second periods, respectively). However, although it has the benefit of time, its number of citations (1024) compared to CSR (3277 and 1540, first and second periods, respectively) is relevant and favorable proportionally (Tables 5-7). The most frequently cited works on this subject are published in the Journal of Business Ethics by the authors Albinger and Freeman (2000) [43]; Collins (2000) [82]; Cornelius, Todres, Janjuha-Jivraj, Woods, and Wallace (2008) [83]; and Holder-Webb, Cohen, Nath, and Wood (2009) [84], with a cumulative 670 citations (65.4% of the total). The existence of a positive relationship between employers performing CSR and the capacity to attract more qualified employees, as well as the impact of the size and typology of the companies for the implementation of CSR policies within them, are some of the issues investigated.
As for Business, it occupies a central position in the matrix of the strategic map, which means that it has an equidistant centrality and density; therefore, it is difficult to glimpse the projection of such a theme. The number of papers is 7, with a total of 343 citations and an H-Index of 7. The most cited authors in this area are Vuontisjarvi (2006) [47] and Bohdanowicz and Zientara (2008) [85], 99 and 83 citations, respectively. In the case of the first paper, it deals with the first steps of the CSR in Finland, demonstrating the lack of awareness and information about it. The second publication is a case study of CSR in hospitality companies, highlighting the implications of CSR for human resource management and support for local communities and the promotion of environmental sustainability.  Source: Prepared by the authors on the basis of SciMAT data.

Period 2010-2014
In the second of the periods designed in this work, due to the increase in the number of documents (from 24 to 78) (Table 4), the increase in the number of keywords incorporated (259), (Figure 3) and, above all, the density in the network of these has led to a greater proliferation of clusters or themes. The driving themes are CSR, Commitment, and Competitive-Advantage, with 77, 33, and 8 documents, respectively. In this period, it is also necessary to highlight the issue of environmental management, not so much because of its centrality, but because of the number of documents and the number of citations to the papers (Table 6).

Period 2010-2014
In the second of the periods designed in this work, due to the increase in the number of documents (from 24 to 78) (Table 4), the increase in the number of keywords incorporated (259), (Figure 3) and, above all, the density in the network of these has led to a greater proliferation of clusters or themes. The driving themes are CSR, Commitment, and Competitive-Advantage, with 77, 33, and 8 documents, respectively. In this period, it is also necessary to highlight the issue of environmental management, not so much because of its centrality, but because of the number of documents and the number of citations to the papers (Table 6).
In terms of CSR, during this period the most frequently cited publications were those of the following authors: Fulmer and Gelfand (2012) [80] [56] with 32 citations. Its topics deal with green marketing strategies, how multinationals manage CSR according to the country where they are located, the importance of using the LEAN method in conjunction with HRM to achieve operations management in a sustainable way, the analysis of SR-HRM from an international perspective, or the promotion of CSR and sustainable development through HR development, for example through employee training or sending them to NGOs.
Finally, in relation to Environmental-Management, the five most cited authors are Mishra and Suar (2010) [87], 186 citations; Dao, Langella, and Carbo (2011) [88], 163; Bohdanowicz, Zientara, and Novotna (2011) [54], 118; Ben Brik, Rettab, and Mellahi (2011) [90], 65;and Wagner (2013) [57] with 52 citations. Many of them also lead the CSR and Commitment clusters. Themes are about the influence of CSR on performance, examining the role of information technology in sustainability beyond the reduction of energy consumption, the relationship of environmental performance to CSR and the close links to HR management, CSR and its impact or market orientation, or analyzing whether the benefits arising for HRM from environmental management activities drive the implementation of the environmental management system.

Period 2015-2019
This last period followed the same line as the previous period. The increase in keywords (400) (Figure 3) and in particular in documents has been particularly high (from 78 to 212) ( Table 4). This generates an enrichment of the theme. The clusters to be highlighted have been, as driving topics, CSR, Green-management and Job, with 206, 35, and 30 documents, respectively (Table 7). Stakeholders also stands out, which, although it is a basic issue, is relevant because of its centrality and the number of documents (39).
With respect to the main subject, CSR, the most cited authors in this period have been Shen [100] with 52 citations. In essence, the issues have been: the level of SR-HRM affect on employees' work behavior when CSR is a social norm, the psychological micro foundations of CSR, reviews of the literature on talent management examining the dominant theoretical frameworks (employee assessment or institutionalism) versus the alternative ones (knowledge management, career or social exchange), the study of synergies between CSR and organizational psychology, and comparative analyses of sustainability and HR reports with companies at an international level.
As for Green-Management, the authors with the most citations have been Dumont, Shen, and Deng

Thematic Networks
In the period 1993-2009, although CSR and HRM with 23 and 13 documents, respectively, were the most published, Business-Ethics with 4 documents, due to its centrality, gave its name to the main cluster ( Figure 5). The research of this cluster had to do with works related, in addition to the previous topics, with organizations and corporate or corporate social performance, financial-performance, behavior, small and medium enterprises (SME) or culture among others. Source: Prepared by the authors on the basis of SciMAT data.

Thematic Networks
In the period 1993-2009, although CSR and HRM with 23 and 13 documents, respectively, were the most published, Business-Ethics with 4 documents, due to its centrality, gave its name to the main cluster ( Figure 5). The research of this cluster had to do with works related, in addition to the previous topics, with organizations and corporate or corporate social performance, financial-performance, behavior, small and medium enterprises (SME) or culture among others. In the period 2010-2014, it is CSR that takes the greatest centrality, passing Business-Ethics to form part of the network with a smaller presence. As for the number of CSR and HRM documents, In the period 2010-2014, it is CSR that takes the greatest centrality, passing Business-Ethics to form part of the network with a smaller presence. As for the number of CSR and HRM documents, they again contain the largest number of publications, 71 and 52, respectively. New topics are incorporated into this cluster such as performance, business, employees, impact, firm-performance, or stakeholders ( Figure 6). In the following period (2015-2019), stakeholders along with behavior-which disappears in this period-take special relevance forming their own clusters.
Finally, between the years 2015-2019, CSR is consolidated as the main driving theme and at the same time leads a network that is becoming increasingly dense. CSR and HRM continue to lead in the number of publications with 203 and 131, respectively. The most striking aspect of this period is the focus on issues related to performance, sustainability, and research-methods-analysis (Figure 7). In the case of the first one, the fact that its growth is substantial, being four times higher (from 24 to 96 documents), shows the clear interest aroused by its study. As for sustainability, which appears for the first time with a total of 86 publications, it maintains a relevant momentum with a clear projection that aims to be in the coming years an independent cluster with a vocation to define itself as a driving theme. With regard to research-methods-analysis, which contains work related to the different methods, indicators, or approaches to address research on CSR and HRM, it has evolved from the first period in which it had only 2 documents to 44 documents in the last period. they again contain the largest number of publications, 71 and 52, respectively. New topics are incorporated into this cluster such as performance, business, employees, impact, firm-performance, or stakeholders ( Figure 6). In the following period (2015-2019), stakeholders along with behavior-which disappears in this period-take special relevance forming their own clusters. Finally, between the years 2015-2019, CSR is consolidated as the main driving theme and at the same time leads a network that is becoming increasingly dense. CSR and HRM continue to lead in the number of publications with 203 and 131, respectively. The most striking aspect of this period is the focus on issues related to performance, sustainability, and research-methods-analysis (Figure 7). In the case of the first one, the fact that its growth is substantial, being four times higher (from 24 to 96 documents), shows the clear interest aroused by its study. As for sustainability, which appears for the first time with a total of 86 publications, it maintains a relevant momentum with a clear projection that aims to be in the coming years an independent cluster with a vocation to define itself as a driving theme. With regard to research-methods-analysis, which contains work related to the different methods, indicators, or approaches to address research on CSR and HRM, it has evolved from the first period in which it had only 2 documents to 44 documents in the last period.

Relevant Issues in the Last Period (2015-2019)
In addition to CSR, Green-Management and Stakeholders have stood out for their centrality in the last period thanks to the importance of their publications with a high level of citations and H-Index. In the case of the former, it is considered a driving theme and contains a total of 35 documents and 311 citations in this period, with an H-Index of 16. The latter is a basic theme that, in this last period, has formed its own cluster, with a growing level of publications (from 19 in the previous period to 35 in this period) and a high number of citations (337), which is expected to become a driving theme in the coming years (Table 7) (Appendix A). Both themes are in full growth and have a high level of travel yet to be explored.
Green-Management (Figure 8) is related to issues such as Environmental-management where research is linked to environmental performance and sustainability or pro-environmental strategies and behavior. Another topic that has considerable weight in the thematic network is Green-human-resource-management in which it is linked to other topics such as Operations-management, Knowledge-management, green supply chain management, or change management for sustainability. One of the contexts where Green-Management has been most studied is the tourism industry. As for the Stakeholders Network (Figure 9), although all the issues are closely related, three ideas seem to be emerging, all of them under the Agency-Theory paradigm which could explain the increased interest in promoting Corporate Social Responsibility in business organizations by stakeholders. First, a subnet appears in which the concepts Corporate and its variants Corporategovernance, Social-performance or Corporate-citizenship are related to Framework and the consequent effect of Environmental-performance. A second idea is woven into the publications that investigate the issues related to Shareholders-Shareholders-value and Strategy or strategic-flexibility. And the third sub-network narrows under the themes Competitive-advantage and Turnover, which are, in turn, related to Strategy and Environmental-performance. As for the Stakeholders Network (Figure 9), although all the issues are closely related, three ideas seem to be emerging, all of them under the Agency-Theory paradigm which could explain the increased interest in promoting Corporate Social Responsibility in business organizations by stakeholders. First, a subnet appears in which the concepts Corporate and its variants Corporate-governance, Social-performance or Corporate-citizenship are related to Framework and the consequent effect of Environmental-performance. A second idea is woven into the publications that investigate the issues related to Shareholders-Shareholders-value and Strategy or strategic-flexibility. And the third sub-network narrows under the themes Competitive-advantage and Turnover, which are, in turn, related to Strategy and Environmental-performance. In this last period, in addition to CSR and Green-Management, issues related to Job, (commitment or transformational-leadership or recruitment, among others), and Drivers (top-management, change-agent, challenges, talent, or critical success factor, among others) have been part of the driving issues. We must also refer to emerging issues such as Exchange, whose work has had to do with socialization, justice, equality, trust or emotions and, finally, a peripheral issue that is also interesting to note, Satisfaction, which has been investigated along with other issues such as business-ethics, flexibility, leadership, identity or individualism, among others.

Conclusions
Corporate Social Responsibility (CSR) and Human Resource Management (HRM) have evolved and interacted over time, but both are described and analyzed from different perspectives. The progress of research in this scientific field has made them related, because of their ecological foundations, but also economic and social, although not without controversy, with sustainability. The implementation of CSR in business organizations and the interconnection with all its subsystems, in particular with HR, has awakened scientific interest, causing literary production that interrelates CSR and HRM to experience an unprecedented boom. More than 67% of all research has taken place in the last five years, but the potential, development, and measurement of both concepts has not been sufficiently explored. Therefore, the aim of this work is to shed light on the scientific production trends of these two concepts in a related way, and to give visibility to the lines of research that try to explain from all possible perspectives and approaches the theoretical and practical effects on sustainability produced by the implementation of CSR-sensitive policies and their integration into HRM.
From the results of the bibliometric analysis, it can be seen that although its evolution has experienced a notable increase, this subject has a short history. The first article appeared in 1993, published by Anderson, in the Journal of Business Ethics [42], which is ultimately the most prolific journal, with 12.1% of the entire sample investigated. In the first period 1993-2009, only 24 documents In this last period, in addition to CSR and Green-Management, issues related to Job, (commitment or transformational-leadership or recruitment, among others), and Drivers (top-management, change-agent, challenges, talent, or critical success factor, among others) have been part of the driving issues. We must also refer to emerging issues such as Exchange, whose work has had to do with socialization, justice, equality, trust or emotions and, finally, a peripheral issue that is also interesting to note, Satisfaction, which has been investigated along with other issues such as business-ethics, flexibility, leadership, identity or individualism, among others.

Conclusions
Corporate Social Responsibility (CSR) and Human Resource Management (HRM) have evolved and interacted over time, but both are described and analyzed from different perspectives. The progress of research in this scientific field has made them related, because of their ecological foundations, but also economic and social, although not without controversy, with sustainability. The implementation of CSR in business organizations and the interconnection with all its subsystems, in particular with HR, has awakened scientific interest, causing literary production that interrelates CSR and HRM to experience an unprecedented boom. More than 67% of all research has taken place in the last five years, but the potential, development, and measurement of both concepts has not been sufficiently explored. Therefore, the aim of this work is to shed light on the scientific production trends of these two concepts in a related way, and to give visibility to the lines of research that try to explain from all possible perspectives and approaches the theoretical and practical effects on sustainability produced by the implementation of CSR-sensitive policies and their integration into HRM.
From the results of the bibliometric analysis, it can be seen that although its evolution has experienced a notable increase, this subject has a short history. The first article appeared in 1993, published by Anderson, in the Journal of Business Ethics [42], which is ultimately the most prolific journal, with 12.1% of the entire sample investigated. In the first period 1993-2009, only 24 documents were published, 7.6% of all literary production. In the following period, between 2010 and 2014, 78 documents (36.4%) are published and, between 2015 and 2019, 212 publications.
From what was analyzed in the first period, it is evident that CSR and HRM, even though they are the most mentioned topics in the research, are not sufficiently related to other topics, and Business-ethics occupied the greatest centrality in all the literature of the moment. There is a demand for more information regarding the CSR in relation to the environment, safety, and HR. The topics that were investigated together with Business-ethics were related to corporate, financial-performance, culture, or behavior, among others.
Between 2010 and 2014, CSR leads the way in centrality, being the main driving theme together with Commitment, Competitive-Advantage. Environmental Management is a basic topic that gets special relevance. During this period there is a certain sensitivity to the effects of SR-HRM on the organizational commitment of employees, the promotion of CSR and sustainable development through HR development, or the relationship of environmental performance with CSR and the close links with HR management. Performance, employees, impact, firm-performance, or stakeholders are issues that are closely related in this period together with CSR and HRM.
In the last period there has been an unprecedented increase in CSR and HRM, which means that their quantitative and qualitative enrichment has led to a multitude of adjacent lines of research. CSR maintains leadership of centrality. The most relevant topics are: Green-management, Job and Drivers (driving topics), Stakeholders (basic topic), Satisfaction (peripheral topic), and Exchange (emerging topic). In this period, the most striking thing in the CSR thematic network is the incorporation for the first time of sustainability, with a very high level of production and, performance and research-methods-analysis with a special evolution from previous periods. Green-management is related to topics such as Environmental-management, Green-human-resource-management, Green supply chain management, or Change management for sustainability. As for Job, its network relates issues such as commitment or transformational-leadership. Drivers are related to topics such as top-management, change-agent, challenges, talent, or critical success factor, among others. Stakeholders, under the paradigm of Agency-Theory weaves different sub-networks related to Corporate, Shareholders-value, and Competitive-advantage. Satisfaction is related to Business-ethics, flexibility, leadership, identity, or individualism, among others. Finally, Exchange is related to socialization, justice, trust, or emotions.
In summary, this work has highlighted the high interest of the scientific community in recent years in CSR and HRM. It has contributed by identifying groups of topics that have recently developed a special interest, and that should continue to be explored in future research such as Green-Management, Stakeholders, Commitment, Competitive-Advantage, Satisfaction, Performance, Sustainability, or Research-methods-analysis, in order to respond to the demands that business organizations have in this respect and to help the total integration of the different approaches related to CSR and HRM.