8D. Maxx, E. B. Tanya. Coming to Terms with Vulnerability.- A Critique o{ The Food Security Definition [J]. Food Policy, 2001, 26 (3).
9L. Dai. Singular Control Systems [M]. New York: Springer-Verlag, 1989.
10C. H. Hommes. Dynamics of the Cobweb Model with Adaptive Expectations and Nonlinear Supply and Demand [J]. Journal of Economic Behaviour and Organization, 1994, 24 (3).