8Bannerjee, "A simple model of herd behavior", Quarterly Journal of Economics, 1992,107:797- 818.
9Bikhcnhandani,S Hirshleifer D ect, Atheory of Fashion, custom, and Cultural Changeas Informational Cas- cades,Journal d Political Economy, 1992,992 - 1026.
10Scharfstein D S,Stein J C,"Herd Behavior and investment',American Economics Review, 1990,80.