This paper examines US airline mergers between 1993 and 2018 and studies their impact on the labor market. Our difference-in-differences estimates indicate a significant reduction in the merging airlines' long-term wage and fringe benefits following the mergers. The effect is particularly salient among large-scale mergers involving major airlines and low cost carriers. The results also suggest a negative short-term employment impact of mergers that varies by occupation types. Our findings are consistent with the impact of merger-induced monopsony power discussed in recent literature and offer important policy implications regarding how to account for employer monopsony power during mergers and acquisitions.
{"title":"Mergers and Labor Market Outcomes in the US Airline Industry","authors":"Myongjin Kim, Q. Ge, Donggeun Kim","doi":"10.2139/ssrn.3615410","DOIUrl":"https://doi.org/10.2139/ssrn.3615410","url":null,"abstract":"This paper examines US airline mergers between 1993 and 2018 and studies their impact on the labor market. Our difference-in-differences estimates indicate a significant reduction in the merging airlines' long-term wage and fringe benefits following the mergers. The effect is particularly salient among large-scale mergers involving major airlines and low cost carriers. The results also suggest a negative short-term employment impact of mergers that varies by occupation types. Our findings are consistent with the impact of merger-induced monopsony power discussed in recent literature and offer important policy implications regarding how to account for employer monopsony power during mergers and acquisitions.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"148 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123256991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this chapter is to explore variation among organizations employing mass production technology. To allow for an apples-to-apples comparison, I examine organizations using essentially the same technologies, making similar products, and competing in the same markets. Specifically, I look at the organizational differences among the largest automakers in the U.S. and Japan.
I focus first on Ford from 1910 to 1930, then General Motors from the 1920s through the 1960s, then Toyota (and other Japanese automakers) from the 1960s through 2000. The differences between these organizations indicate that, while technology shapes organizations within broad limits, it does not determine an organization’s complete design or its long-term competitive success or failure.
{"title":"Design Rules, Volume 2: Chapter 10—Variations on the Theme of Mass Production","authors":"Carliss Y. Baldwin","doi":"10.2139/ssrn.3717875","DOIUrl":"https://doi.org/10.2139/ssrn.3717875","url":null,"abstract":"The purpose of this chapter is to explore variation among organizations employing mass production technology. To allow for an apples-to-apples comparison, I examine organizations using essentially the same technologies, making similar products, and competing in the same markets. Specifically, I look at the organizational differences among the largest automakers in the U.S. and Japan. <br><br>I focus first on Ford from 1910 to 1930, then General Motors from the 1920s through the 1960s, then Toyota (and other Japanese automakers) from the 1960s through 2000. The differences between these organizations indicate that, while technology shapes organizations within broad limits, it does not determine an organization’s complete design or its long-term competitive success or failure.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128675975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the impact of regulatory risk on vertical integration and upstream investment by a regulated firm that provides an essential input to downstream competitors. Regulatory risk reflects uncertainty about the regulator's commitment to a regulatory policy that promotes the regulated firm's unobservable investment effort. We show that, when the regulator sets the regulatory policy after the vertical industry structure has been established, some degree of regulatory risk is ex ante socially beneficial. Regulatory risk makes vertical integration profitable and stimulates upstream investment at a lower social cost. This occurs for moderate costs of investment effort and firm small risk aversion. Our analysis sheds new light on some relevant empirical patterns in vertically related markets.
{"title":"Regulatory Risk, Vertical Integration, and Upstream Investment","authors":"Raffaele Fiocco, Dongyu Guo","doi":"10.2139/ssrn.3513753","DOIUrl":"https://doi.org/10.2139/ssrn.3513753","url":null,"abstract":"We investigate the impact of regulatory risk on vertical integration and upstream investment by a regulated firm that provides an essential input to downstream competitors. Regulatory risk reflects uncertainty about the regulator's commitment to a regulatory policy that promotes the regulated firm's unobservable investment effort. We show that, when the regulator sets the regulatory policy after the vertical industry structure has been established, some degree of regulatory risk is ex ante socially beneficial. Regulatory risk makes vertical integration profitable and stimulates upstream investment at a lower social cost. This occurs for moderate costs of investment effort and firm small risk aversion. Our analysis sheds new light on some relevant empirical patterns in vertically related markets.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121124036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michele G. Giuranno, Marcella Scrimitore, G. Stamatopoulos
It is widely believed that vertical integration in an environment without foreclosure, or more generally without any mechanism that restricts competition among firms, raises the welfare of consumers. In this paper we show that this can be overturned in a standard setting. We consider a vertical structure where each downstream firm purchases an input from its exclusive upstream supplier in the presence of a welfare maximizing government which taxes/subsidizes the product of the downstream market. We show that a single or multiple vertical integrations alter the optimal governmental policy in a way that hurts consumers: integration induces the government to reduce the optimal subsidy and, as a result, industry output and consumer welfare.
{"title":"Vertical Integration under an Optimal Tax Policy: A Consumer Surplus Detrimental Result","authors":"Michele G. Giuranno, Marcella Scrimitore, G. Stamatopoulos","doi":"10.2139/ssrn.3475378","DOIUrl":"https://doi.org/10.2139/ssrn.3475378","url":null,"abstract":"It is widely believed that vertical integration in an environment without foreclosure, or more generally without any mechanism that restricts competition among firms, raises the welfare of consumers. In this paper we show that this can be overturned in a standard setting. We consider a vertical structure where each downstream firm purchases an input from its exclusive upstream supplier in the presence of a welfare maximizing government which taxes/subsidizes the product of the downstream market. We show that a single or multiple vertical integrations alter the optimal governmental policy in a way that hurts consumers: integration induces the government to reduce the optimal subsidy and, as a result, industry output and consumer welfare.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114590154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate whether the organizational design of manufacturing production is sensitive to important advances in information technology (IT) – and under what conditions. Using U.S. Census Bureau data for over 5,600 plants from 1992 to 2002, we observe both specific uses of IT and whether plants outsource downstream value-chain activities or keep them within the firm. Taking advantage of the sudden introduction of the commercial internet in the mid-1990s and within-plant changes over this period, we find that externally-focused coordination over the internet was associated with a significant net shift towards market-based exchange. The magnitude of the response depends, however, on the pre-existing organization of internal production processes – which varies widely not only across, but also within firms. Moreover, the effects vary by the particular application(s) of general-purpose internet technology. By studying vertical integration at the level of transaction flows and considering important features of how production is organized inside firms, we surface new facets of the relationship between IT and firm organization in an increasingly digital age.
{"title":"Firm Organization in the Digital Age: IT Use and Vertical Transactions in U.S. Manufacturing","authors":"Kristina McElheran, Chris M. Forman","doi":"10.2139/ssrn.3396116","DOIUrl":"https://doi.org/10.2139/ssrn.3396116","url":null,"abstract":"We investigate whether the organizational design of manufacturing production is sensitive to important advances in information technology (IT) – and under what conditions. Using U.S. Census Bureau data for over 5,600 plants from 1992 to 2002, we observe both specific uses of IT and whether plants outsource downstream value-chain activities or keep them within the firm. Taking advantage of the sudden introduction of the commercial internet in the mid-1990s and within-plant changes over this period, we find that externally-focused coordination over the internet was associated with a significant net shift towards market-based exchange. The magnitude of the response depends, however, on the pre-existing organization of internal production processes – which varies widely not only across, but also within firms. Moreover, the effects vary by the particular application(s) of general-purpose internet technology. By studying vertical integration at the level of transaction flows and considering important features of how production is organized inside firms, we surface new facets of the relationship between IT and firm organization in an increasingly digital age.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127391837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Employment of physicians by hospitals – typically referred to as vertical integration – has increased significantly. Received theories fail to explain a key fact: The extent of vertical integration in not-for-profit (NFP) hospitals is substantially higher than in for-profit (FP) hospitals. We develop a model in which vertical externalities in the joint provision of complementary health care services by independent hospitals and physicians cause total prices and cost to be higher, and quantity, quality and profits to be lower, relative to a vertically integrated organization. This establishes an incentive for hospitals to integrate. We show that these externalities impact NFP hospitals more than they do FPs, so that NFPs have stronger incentives to integrate. Using data on US hospitals from 2000-2015 and with controls for other covariates including state-level “corporate-practice-of-medicine” regulations, we find support for our predictions. Our model not only explains patterns of vertical integration observed in the US hospital industry, but also has surprising implications for the effects of such integration on hospital and physician prices, and hence, for antitrust policy and empirical studies of pricing.
{"title":"Hospital-Physician Integration and Hospital Ownership","authors":"R. Hansen, A. K. Sundaram","doi":"10.2139/ssrn.3401559","DOIUrl":"https://doi.org/10.2139/ssrn.3401559","url":null,"abstract":"Employment of physicians by hospitals – typically referred to as vertical integration – has increased significantly. Received theories fail to explain a key fact: The extent of vertical integration in not-for-profit (NFP) hospitals is substantially higher than in for-profit (FP) hospitals. We develop a model in which vertical externalities in the joint provision of complementary health care services by independent hospitals and physicians cause total prices and cost to be higher, and quantity, quality and profits to be lower, relative to a vertically integrated organization. This establishes an incentive for hospitals to integrate. We show that these externalities impact NFP hospitals more than they do FPs, so that NFPs have stronger incentives to integrate. Using data on US hospitals from 2000-2015 and with controls for other covariates including state-level “corporate-practice-of-medicine” regulations, we find support for our predictions. Our model not only explains patterns of vertical integration observed in the US hospital industry, but also has surprising implications for the effects of such integration on hospital and physician prices, and hence, for antitrust policy and empirical studies of pricing.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"49 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123186392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Social progress through improved treatment of minority groups (e.g., forbidding racial or sexual harassment) may or may not spread to corporate cultures through competition. We provide a theory of corporate culture, and we show that emergent, progressive corporate cultures can displace existing, regressive ones only when the prevailing wage gap is large between majority and minority groups. Wider cultural differences between groups make progress less likely. The model provides testable predictions on racial and gender wage gaps across firms.
{"title":"Social Progress and Corporate Culture","authors":"Gary B. Gorton, Alexander Zentefis","doi":"10.2139/ssrn.3316345","DOIUrl":"https://doi.org/10.2139/ssrn.3316345","url":null,"abstract":"\u0000 Social progress through improved treatment of minority groups (e.g., forbidding racial or sexual harassment) may or may not spread to corporate cultures through competition. We provide a theory of corporate culture, and we show that emergent, progressive corporate cultures can displace existing, regressive ones only when the prevailing wage gap is large between majority and minority groups. Wider cultural differences between groups make progress less likely. The model provides testable predictions on racial and gender wage gaps across firms.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126325227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper introduces the V-form organisation, a new form of firm organisation where vertical integration is outsourced to a decentralized distributed ledger (a blockchain). V-form organisations rely on the coordination of a (trusted) third party. It looks specifically at two instances of V-form organisation being established on the IBM-Linux Foundation Hyperledger permissioned blockchain. The paper concludes with four recommendations for strategic management about how to adjust to a V-form world, and four recommendations for policymakers.
{"title":"Outsourcing Vertical Integration: Distributed Ledgers and the V-Form Organisation","authors":"C. Berg, S. Davidson, J. Potts","doi":"10.2139/ssrn.3300506","DOIUrl":"https://doi.org/10.2139/ssrn.3300506","url":null,"abstract":"This paper introduces the V-form organisation, a new form of firm organisation where vertical integration is outsourced to a decentralized distributed ledger (a blockchain). V-form organisations rely on the coordination of a (trusted) third party. It looks specifically at two instances of V-form organisation being established on the IBM-Linux Foundation Hyperledger permissioned blockchain. The paper concludes with four recommendations for strategic management about how to adjust to a V-form world, and four recommendations for policymakers.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115111524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Korean Abstract: 본 연구는 남북한 경제통합이 남북 양 경제에 미치는 파급효과를 규명하기 위해 모형을 구축하고 성장효과를 분석하고자 하였다. 먼저 제1장에서는 본 연구의 배경과 목적, 기존 연구와의 방법론적 차별점을 제시하였다. 남북경제협력사업은 역대 정부마다 새로운 경제성장의 기회로 여겨왔으나 중요성에 반해 경제적 파급효과를 추정한 연구가 거의 없었다. 본 연구는 남북통일과 더불어 남북경협이 남북한 양측에 미치는 경제성장효과를 추정하고 남북 양 경제의 이익을 극대화하는 남북 경협 형태를 규명하여 시사점을 도출하는 것을 목적으로 한다. 방법론적으로는 솔로우 성장모형을 사용한 점, 다양한 경협사업 및 정책변수를 고려하여 경제성장효과를 추정한 점, 동태 분석을 하여 기간별 성장효과를 확인한 점 등이 기존 선행연구와의 차별점으로 평가된다. English Abstract: The purpose of this study is to construct a model that can analyze growth effects to explain the impact that economic integration between North and South Korea will have on both economies. The main results of this study are as follows: first, by constructing the analysis model for economic integration on North and South Korea, the effects of economic integration on North and South Korea were estimated simultaneously, and economic cooperation and unification estimated with the same model; second, the effect of inter-Korean economic cooperation on North Korean productivity was internalized within the model; third, the main variables for evaluation of the North Korean economy were provided; and fourth, through these analyses we propose the economic cooperation projects most likely to maximize the economic growth of the two Koreas.
Korean Abstract:本研究为查明南北韩经济统合对南北两大经济产生的波及效果，构建模型，分析增长效果。首先，第一章提出了本研究的背景和目的，以及与现有研究的方法论上的区别。历届政府都将南北经济合作事业视为新的经济增长机会，但与其重要性相反，几乎没有研究推测经济波及效果。本研究的目的是，在南北统一的同时，推测南北经济合作对南北韩双方产生的经济增长效果，查明使南北两国经济利益最大化的南北经济合作形态，得出启示点。在方法论上，使用solo增长模型、考虑多种经济合作事业及政策变数推定经济增长效果、进行动态分析，确认各期间的增长效果等被评价为与现有先行研究的不同点。english abstract:The purpose of this study is to construct a model that can analyze growth effects to explain The impact that economic integration between North and South Korea will have on both economies。study are as followsfirst, by constructing the analysis model for economic integration on North and South Korea, the effects of economic integration on North and South Korea were estimated simultaneously，经济合作与统一estimated with the same model;effect of inter-Korean economic cooperation on North Korean productivity was internalized within the model;third, the main variables for evaluation of the North Korean economy were provided;and fourth, through these analyses我们propose the economic cooperation projects most likely to maximize the economic growth of the two korea。
{"title":"남북한 경제통합 분석모형 구축과 성장효과 분석(Developing Analysis Model and Analizing Growth Effect of South and North Korea Economic Integration)","authors":"Jangho Choi, Bumhwan Kim","doi":"10.2139/SSRN.3160435","DOIUrl":"https://doi.org/10.2139/SSRN.3160435","url":null,"abstract":"<b>Korean Abstract: </b>본 연구는 남북한 경제통합이 남북 양 경제에 미치는 파급효과를 규명하기 위해 모형을 구축하고 성장효과를 분석하고자 하였다. 먼저 제1장에서는 본 연구의 배경과 목적, 기존 연구와의 방법론적 차별점을 제시하였다. 남북경제협력사업은 역대 정부마다 새로운 경제성장의 기회로 여겨왔으나 중요성에 반해 경제적 파급효과를 추정한 연구가 거의 없었다. 본 연구는 남북통일과 더불어 남북경협이 남북한 양측에 미치는 경제성장효과를 추정하고 남북 양 경제의 이익을 극대화하는 남북 경협 형태를 규명하여 시사점을 도출하는 것을 목적으로 한다. 방법론적으로는 솔로우 성장모형을 사용한 점, 다양한 경협사업 및 정책변수를 고려하여 경제성장효과를 추정한 점, 동태 분석을 하여 기간별 성장효과를 확인한 점 등이 기존 선행연구와의 차별점으로 평가된다. <b>English Abstract: </b>The purpose of this study is to construct a model that can analyze growth effects to explain the impact that economic integration between North and South Korea will have on both economies. The main results of this study are as follows: first, by constructing the analysis model for economic integration on North and South Korea, the effects of economic integration on North and South Korea were estimated simultaneously, and economic cooperation and unification estimated with the same model; second, the effect of inter-Korean economic cooperation on North Korean productivity was internalized within the model; third, the main variables for evaluation of the North Korean economy were provided; and fourth, through these analyses we propose the economic cooperation projects most likely to maximize the economic growth of the two Koreas.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"213 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114357197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I examine the impact of M&As on employment dynamics and the composition of human capital in target firms. Using detailed employer-employee administrative data linked with hand-collected information on M&A activity in Brazil, I find that M&As are associated with a significant decline in employment, primarily through an increase in involuntary separations and a decline in hirings. This employment decline reflects efficiency-seeking restructuring. Target firms increase the share of high-skill and non-routine employees, while reducing costs through efficient consolidation and elimination of occupational overlap. The primary mechanism that explains these shifts is the adoption of innovation-intensive practices and investment in IT, particularly by acquirers that have the knowledge and ability to do so. Finally, post-merger compositional changes lead to an increase in wages and within-firm wage inequality.
{"title":"Corporate Takeovers and Labor Restructuring","authors":"S. Lagaras","doi":"10.2139/ssrn.3222950","DOIUrl":"https://doi.org/10.2139/ssrn.3222950","url":null,"abstract":"I examine the impact of M&As on employment dynamics and the composition of human capital in target firms. Using detailed employer-employee administrative data linked with hand-collected information on M&A activity in Brazil, I find that M&As are associated with a significant decline in employment, primarily through an increase in involuntary separations and a decline in hirings. This employment decline reflects efficiency-seeking restructuring. Target firms increase the share of high-skill and non-routine employees, while reducing costs through efficient consolidation and elimination of occupational overlap. The primary mechanism that explains these shifts is the adoption of innovation-intensive practices and investment in IT, particularly by acquirers that have the knowledge and ability to do so. Finally, post-merger compositional changes lead to an increase in wages and within-firm wage inequality.","PeriodicalId":230377,"journal":{"name":"ERN: Integration (Topic)","volume":"189 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133168381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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