5Gollop F M, Monahan J L. A Generalized Index of Diversification : Trends in U. S. Manufacturing [ J ]. The Review of Economics and Statistics, 1991 (73) :318 - 330.
6Leslie E Palich, Laura B Cardinal, Chet Miller C. Curvilinearity in the Diversification - performance Linkage: An Examination of Over Three Decades of Research[J] .Strategic Management Journal,2000(21):155- 174.
7Berger P G, Ofek E. Diversification' s Effect on Firm Value[ J ]. Journal of Financial Economics, 1995 (37) :39 - 65.
8Soon Cheul Lee. Corporate Diversification and Performance : Evidence From Korea[ D ] Norman : University of Oklahoma, 2002.