4REBECCA S, DEMSETZ P E. 1997. Diversification, size and risk at bank holding companies[ J]. Journal of Mon- ey, Credit and Banking, 29(3) : 300 -313.
5DI~LLMANN K, MASSCHELEIN N. 2007. A tractable model to measure sector concentration risk in credit port- folios[ J]. Journal of Financial Services Research, 32 (8) : 55 -79.
6KALOTYCHOU E, STALKOURAS S K. 2006. An empiri- cal investigation of the loan concentration risk in latin america[ J ]. Journal of Multinational Financial Manage- ment,16(4) : 363 -384.