5Berger and Udell. Small Business Credit Availability and Relationship Lending: The Importance of Bank Organizational Structure[J], The Economic Journal. 2002,FebrnmT .
6Ayyagari M. Small and Medium Enterprises Across the Globe [R]. Washington, DC: World Bank, 2008-11.
7Berger AN, Udell G. Relationship Lending and Lines of Credit in Small Firm Finance [J]. Journal of Business, 1995, 68(3): 351-381.