This paper examines how tax policy should be designed to best encourage entrepreneurial activity in start-up firms. We begin by describing several presumed market failures affecting entrepreneurial firms that would lead to an under-provision of entrepreneurial activity: 1) information spillovers from innovations in entrepreneurial firms to other firms, 2) positive externalities to consumers from innovative new products sold by these firms, and 3) lemons problems in the market for both debt and equity issued by these firms. We then analyze the degree to which various tax policy measures can alleviate these failures. A key complication we focus on is the inability of the government to observe which, and the degree to which, any given start-up firm is entrepreneurial. This forces policy to target behavioral differences between entrepreneurial and non-entrepreneurial start-ups. We presume that start-up firms, to the degree they are entrepreneurial, face upfront costs in developing and marketing a new technology, and in the process face substantial risk. Our analysis then suggests the use of refundable tax savings from business losses in start-ups together with a compensating surtax on the profits of start-ups (needed in the case of lemons problems) to help alleviate the various market failures faced by entrepreneurial start-ups.
{"title":"How Should Taxes Be Designed to Encourage Entrepreneurship?","authors":"Roger H Sarada, R. Gordon","doi":"10.2139/ssrn.2896431","DOIUrl":"https://doi.org/10.2139/ssrn.2896431","url":null,"abstract":"This paper examines how tax policy should be designed to best encourage entrepreneurial activity in start-up firms. We begin by describing several presumed market failures affecting entrepreneurial firms that would lead to an under-provision of entrepreneurial activity: 1) information spillovers from innovations in entrepreneurial firms to other firms, 2) positive externalities to consumers from innovative new products sold by these firms, and 3) lemons problems in the market for both debt and equity issued by these firms. We then analyze the degree to which various tax policy measures can alleviate these failures. A key complication we focus on is the inability of the government to observe which, and the degree to which, any given start-up firm is entrepreneurial. This forces policy to target behavioral differences between entrepreneurial and non-entrepreneurial start-ups. We presume that start-up firms, to the degree they are entrepreneurial, face upfront costs in developing and marketing a new technology, and in the process face substantial risk. Our analysis then suggests the use of refundable tax savings from business losses in start-ups together with a compensating surtax on the profits of start-ups (needed in the case of lemons problems) to help alleviate the various market failures faced by entrepreneurial start-ups.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114985919","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}
Francophone African countries have made a tremendous effort in harmonising domestic standards and reporting with the International Financial Reporting Standards (IFRS). Moving from two distinct OCAM streams to two OHADA streams (effective 1985) and now one OHADA Uniform Accounting Act embodying 17 member countries (effective 2001) is a milestone towards harmonisation of reporting practice both domestically and internationally. This empirical study examines whether the effort of harmonisation, especially after the 2001 standards has resulted in the successful convergence of firms' accounting practices by analysing public limited liability companies' compliance with the OHADA Uniform Accounting Act and if such compliance has improved over time. The study has been carried out using the 2008 and 2009 annual reports of three public limited companies in the OHADA zone that translate their financial statements into IFRS. The ranks of closeness and compliance index have been used to analyse data. Findings reveal a relatively high level of compliance with the accounting regulation by sampling limited liability companies. The results also give an indication of harmonisation in accounting practice of limited companies within member countries as they were found to be substantially consistent in compliance, especially in countries that have instituted the Statistics and Tax returns (or "DSF") as a reporting medium.
{"title":"Assessment of Compliance With OHADA Uniform Accounting Act by Public Limited Companies","authors":"Michael Forzeh Fossung","doi":"10.2139/ssrn.3433424","DOIUrl":"https://doi.org/10.2139/ssrn.3433424","url":null,"abstract":"Francophone African countries have made a tremendous effort in harmonising domestic standards and reporting with the International Financial Reporting Standards (IFRS). Moving from two distinct OCAM streams to two OHADA streams (effective 1985) and now one OHADA Uniform Accounting Act embodying 17 member countries (effective 2001) is a milestone towards harmonisation of reporting practice both domestically and internationally. This empirical study examines whether the effort of harmonisation, especially after the 2001 standards has resulted in the successful convergence of firms' accounting practices by analysing public limited liability companies' compliance with the OHADA Uniform Accounting Act and if such compliance has improved over time. The study has been carried out using the 2008 and 2009 annual reports of three public limited companies in the OHADA zone that translate their financial statements into IFRS. The ranks of closeness and compliance index have been used to analyse data. Findings reveal a relatively high level of compliance with the accounting regulation by sampling limited liability companies. The results also give an indication of harmonisation in accounting practice of limited companies within member countries as they were found to be substantially consistent in compliance, especially in countries that have instituted the Statistics and Tax returns (or \"DSF\") as a reporting medium.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116004267","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 investigates the relation between employment protection and corporate liquidity management (i.e., cash holding and cash saving decisions). Theory suggests that employment protection increases firms' labor adjustment costs. We use difference-in-difference estimation method exploiting changes in employment protection laws as a source of variation in labor adjustment costs in 20 countries over the period 1990-2007. We find that, in response to an increase in employment protection, firms increase their cash buffers and propensities to save cash from the funds raised internally and externally. The effect is stronger for firms with relatively small size, high cash flow volatility, and high labor intensity. Overall, our findings suggest that firms' precautionary motives for cash savings increase as labor adjustment costs and therefore operating leverage increases.
{"title":"Employment Protection Laws and Corporate Cash Holdings","authors":"Ahmet Karpuz, Kirak Kim, Neslihan Ozkan","doi":"10.2139/ssrn.2773072","DOIUrl":"https://doi.org/10.2139/ssrn.2773072","url":null,"abstract":"This paper investigates the relation between employment protection and corporate liquidity management (i.e., cash holding and cash saving decisions). Theory suggests that employment protection increases firms' labor adjustment costs. We use difference-in-difference estimation method exploiting changes in employment protection laws as a source of variation in labor adjustment costs in 20 countries over the period 1990-2007. We find that, in response to an increase in employment protection, firms increase their cash buffers and propensities to save cash from the funds raised internally and externally. The effect is stronger for firms with relatively small size, high cash flow volatility, and high labor intensity. Overall, our findings suggest that firms' precautionary motives for cash savings increase as labor adjustment costs and therefore operating leverage increases.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123847456","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 studies the effect of different domestic institutions (property rights, corporate governance, and financial efficiency) on the net direction of different international capital flows (FDI and financial capital) in an empirical setting by taking the theoretical framework designed in Ju and Wei (2010) as a basis. Using a panel dataset for 123 countries covering the period 2006-2014 the results confirm the two-way direction of different international capital flows. The strength of property rights protection is found to have a statistically significant negative lagged effect on net FDI leading to a net outflow of FDI at relatively higher levels of property rights protection. Better corporate governance and financial efficiency is found to have a statistically significant positive effect on net financial capital leading to a net inflow of financial capital at relatively higher levels of financial system efficiency. The relationships holds for different specifications of the model although property rights becomes insignificant once the model has been corrected for potential autocorrelation and heteroskedasticity. Furthermore, there is potential reverse causality between institutions and capital flows that needs to be addressed using a proper time-variant instrument.
本文以Ju and Wei(2010)设计的理论框架为基础，实证研究了不同国内制度(产权、公司治理和金融效率)对不同国际资本流动(FDI和金融资本)净方向的影响。使用涵盖2006-2014年123个国家的面板数据集，结果证实了不同国际资本流动的双向性。研究发现，产权保护力度对净FDI具有统计上显著的负滞后效应，导致在相对较高的产权保护水平下，FDI净流出。研究发现，更好的公司治理和财务效率对净金融资本有统计学上显著的正向影响，导致在相对较高的金融体系效率水平下，金融资本净流入。这种关系适用于模型的不同规格，尽管一旦模型被修正为潜在的自相关和异方差，产权就变得无关紧要。此外，制度和资本流动之间存在潜在的反向因果关系，需要使用适当的时变工具来解决。
{"title":"The Role of Institutions on the Direction of International Capital Flows","authors":"Rüçhan Kamil Altun","doi":"10.2139/ssrn.2932973","DOIUrl":"https://doi.org/10.2139/ssrn.2932973","url":null,"abstract":"This paper studies the effect of different domestic institutions (property rights, corporate governance, and financial efficiency) on the net direction of different international capital flows (FDI and financial capital) in an empirical setting by taking the theoretical framework designed in Ju and Wei (2010) as a basis. Using a panel dataset for 123 countries covering the period 2006-2014 the results confirm the two-way direction of different international capital flows. The strength of property rights protection is found to have a statistically significant negative lagged effect on net FDI leading to a net outflow of FDI at relatively higher levels of property rights protection. Better corporate governance and financial efficiency is found to have a statistically significant positive effect on net financial capital leading to a net inflow of financial capital at relatively higher levels of financial system efficiency. The relationships holds for different specifications of the model although property rights becomes insignificant once the model has been corrected for potential autocorrelation and heteroskedasticity. Furthermore, there is potential reverse causality between institutions and capital flows that needs to be addressed using a proper time-variant instrument.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131779024","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 aim of this paper is to identify the driving forces of Sovereign wealth funds' investments. For this, we develop an original econometric framework that quantifies the role of spatial dependence in the location of investments, and uses the Inverse Hyperbolic Sine transformation of the dependent variable in a spatial panel model context. This transformation copes with two features of net flows, namely an highly skewed distribution and the presence of zero and negative values. Using a large-scale database, we provide evidence of negative spatial dependence, investments in one country being on average at the expense of its neighbors.
{"title":"Spatial Dependence in Sovereign Wealth Funds' Investments","authors":"Nicolas Debarsy, J. Gnabo, Malik Kerkour","doi":"10.2139/ssrn.2711354","DOIUrl":"https://doi.org/10.2139/ssrn.2711354","url":null,"abstract":"The aim of this paper is to identify the driving forces of Sovereign wealth funds' investments. For this, we develop an original econometric framework that quantifies the role of spatial dependence in the location of investments, and uses the Inverse Hyperbolic Sine transformation of the dependent variable in a spatial panel model context. This transformation copes with two features of net flows, namely an highly skewed distribution and the presence of zero and negative values. Using a large-scale database, we provide evidence of negative spatial dependence, investments in one country being on average at the expense of its neighbors.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127042689","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 provides an overview of the potential for and constraints to using broadband channels and applications to increase financial inclusion globally and specifically in Latin America. We review ten different financial service opportunity areas, including savings services with enhanced personalization options, merchant cash advances, P2P lending and crowdfunding platforms, online lenders leveraging users' digital footprint, and financial education.
{"title":"Using Broadband to Enhance Financial Inclusion","authors":"Ignacio Mas","doi":"10.2139/SSRN.1555053","DOIUrl":"https://doi.org/10.2139/SSRN.1555053","url":null,"abstract":"This paper provides an overview of the potential for and constraints to using broadband channels and applications to increase financial inclusion globally and specifically in Latin America. We review ten different financial service opportunity areas, including savings services with enhanced personalization options, merchant cash advances, P2P lending and crowdfunding platforms, online lenders leveraging users' digital footprint, and financial education.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122452430","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}
Chapter 11 provides a conclusion to the book "Stakeholder protection in cross-border company seat transfers in the EU" and gives an overview of the analysis as to whether stakeholders such as shareholders, creditors, employees or the society at large are at risk in such seat transfers and if so, how the stakeholders can be protected. Finally, the conclusion gives policy recommendations.
{"title":"Chapter 11 - Cross-Border Company Seat Transfers in the EU - Conclusion","authors":"Thomas Biermeyer","doi":"10.2139/ssrn.2837424","DOIUrl":"https://doi.org/10.2139/ssrn.2837424","url":null,"abstract":"Chapter 11 provides a conclusion to the book \"Stakeholder protection in cross-border company seat transfers in the EU\" and gives an overview of the analysis as to whether stakeholders such as shareholders, creditors, employees or the society at large are at risk in such seat transfers and if so, how the stakeholders can be protected. Finally, the conclusion gives policy recommendations.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122692290","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}
type="main" xml:id="ecot12068-abs-0001"> A large literature asserts a causal relationship between the quality of economic governance and economic performance. However, attempts to establish such a link at an aggregate level have met with considerable methodological criticism. This paper seeks to overcome this limitation. We match a panel of Vietnamese enterprises from 2006 to 2010 with a unique panel dataset measuring sub-national economic governance to estimate a relationship between local governance and private investment. We do not find a significant relationship between investment and most traditional forms of governance. However, there is one important exception – transparency, especially the public posting of planning documents, is strongly associated with higher investment across a range of different specifications. Our results have significant implications for policy, given the prevailing theory that changes in the quality of local economic governance will spur improved economic performance.
{"title":"The Impact of Governance and Transparency on Firm Investment in Vietnam","authors":"Edmund J. Malesky, N. McCulloch, Nguyen Duc Nhat","doi":"10.1111/ecot.12068","DOIUrl":"https://doi.org/10.1111/ecot.12068","url":null,"abstract":"type=\"main\" xml:id=\"ecot12068-abs-0001\"> A large literature asserts a causal relationship between the quality of economic governance and economic performance. However, attempts to establish such a link at an aggregate level have met with considerable methodological criticism. This paper seeks to overcome this limitation. We match a panel of Vietnamese enterprises from 2006 to 2010 with a unique panel dataset measuring sub-national economic governance to estimate a relationship between local governance and private investment. We do not find a significant relationship between investment and most traditional forms of governance. However, there is one important exception – transparency, especially the public posting of planning documents, is strongly associated with higher investment across a range of different specifications. Our results have significant implications for policy, given the prevailing theory that changes in the quality of local economic governance will spur improved economic performance.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130895871","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}
In this paper, we investigate the pricing of crack spread options. Particular emphasis is placed on the question of whether univariate modeling of the crack spread or explicit modeling of the two underlyings is preferable. Therefore, we contrast a bivariate GARCH volatility model for cointegrated underlyings with the alternative of modeling the crack spread directly. Conducting an empirical analysis of crude oil/heating oil and crude oil/gasoline crack spread options traded on the New York Mercantile Exchange, the more simplistic univariate approach is found to be superior with respect to option pricing performance.
{"title":"An Empirical Model Comparison for Valuing Crack Spread Options","authors":"Steffen Mahringer, Marcel Prokopczuk","doi":"10.2139/ssrn.1557006","DOIUrl":"https://doi.org/10.2139/ssrn.1557006","url":null,"abstract":"In this paper, we investigate the pricing of crack spread options. Particular emphasis is placed on the question of whether univariate modeling of the crack spread or explicit modeling of the two underlyings is preferable. Therefore, we contrast a bivariate GARCH volatility model for cointegrated underlyings with the alternative of modeling the crack spread directly. Conducting an empirical analysis of crude oil/heating oil and crude oil/gasoline crack spread options traded on the New York Mercantile Exchange, the more simplistic univariate approach is found to be superior with respect to option pricing performance.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126476570","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}
Financial markets have become vital tools for sustaining the economies of developing countries to this, many developing countries have embarked on a number of financial sector developments, the government of Ghana as part of the structural adjustment programme launched the Financial Sector Adjustment Programme (FINSAP) to address the deterioration problems in the financial sector. But Ghana still lacks a well-established banking sector and local commercial banks usually find it difficult to provide long-term loans for infrastructure projects. Infrastructure projects often require funding that would exceed the amount that a commercial bank can lend to a single customer under banking regulations. They are not well positioned to finance infrastructure that is intended to generate revenues over 20 to 30 years.Therefore in order to meet the country’s infrastructure financing needs, there is the need to fall on a substantial larger financial option to finance local infrastructure and projects. Ghana’s Local infrastructure projects typically involve a large investment of funds over several years and the expectation of the Priority Action Plan by African Development Bank has necessitated the need of issuing municipal bond to finance it infrastructure projects It was in this light that this paper focused on the constraints and challenges to the development and the implementation of a domestic bond market, and the applicability of such experiences to Ghana. The study specifically analyzed the challenges hindering the development and implementation of municipal bond market in Ghana.The study concludes that Current sources of finance for government of Ghana can’t meet the 10-30 years developmental needs of Ghana so there is the need for municipal bond market to issue municipal bonds. But Government of Ghana hasn’t made much concerted effort by putting a legal or operational framework in place which would enable metropolitan, municipal and district assemblies to issue bonds to finance their infrastructure projects.
{"title":"Constraints to the Development of A Fully-Fledged Municipal Bond Market in Ghana","authors":"N. O. Ansah","doi":"10.2139/ssrn.2647391","DOIUrl":"https://doi.org/10.2139/ssrn.2647391","url":null,"abstract":"Financial markets have become vital tools for sustaining the economies of developing countries to this, many developing countries have embarked on a number of financial sector developments, the government of Ghana as part of the structural adjustment programme launched the Financial Sector Adjustment Programme (FINSAP) to address the deterioration problems in the financial sector. But Ghana still lacks a well-established banking sector and local commercial banks usually find it difficult to provide long-term loans for infrastructure projects. Infrastructure projects often require funding that would exceed the amount that a commercial bank can lend to a single customer under banking regulations. They are not well positioned to finance infrastructure that is intended to generate revenues over 20 to 30 years.Therefore in order to meet the country’s infrastructure financing needs, there is the need to fall on a substantial larger financial option to finance local infrastructure and projects. Ghana’s Local infrastructure projects typically involve a large investment of funds over several years and the expectation of the Priority Action Plan by African Development Bank has necessitated the need of issuing municipal bond to finance it infrastructure projects It was in this light that this paper focused on the constraints and challenges to the development and the implementation of a domestic bond market, and the applicability of such experiences to Ghana. The study specifically analyzed the challenges hindering the development and implementation of municipal bond market in Ghana.The study concludes that Current sources of finance for government of Ghana can’t meet the 10-30 years developmental needs of Ghana so there is the need for municipal bond market to issue municipal bonds. But Government of Ghana hasn’t made much concerted effort by putting a legal or operational framework in place which would enable metropolitan, municipal and district assemblies to issue bonds to finance their infrastructure projects.","PeriodicalId":417524,"journal":{"name":"FEN: Other International Corporate Finance (Topic)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126448038","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：