5Wang J F, Huang L H, Guo Z Y. Dynamical behavior of delayed Hopfield neural networks with discontinuous activations[J]. Applied Mathematical Modelling, 2009, 33: 1793-1802.
6Huang L H, Wang J F, Zhou X n. Existence and global asymptotic stability of periodic for Hopfield neural networks with discontinuous activations[J]. Nonlinear Analysis: Real world Applications, 2009, 10: 1651-1661.
7Arefeh B., Mohammad B M. Fractional-Order Hopfield neural networks[C]. M.Koppen et al. (Eds.): ICONIP 2008, Part I, LNCS 5506, 2009: 883-890.
8Diethelm K, Ford N J. Analysis of fractional differential equations[J]. J Math Aanl Appl, 2002, 265(2): 229-248.
9Zhang S Q. The existence of a positive solution for a nonlinear fractional differential equation[J]. J Math Anal Appl, 2000, 252(2): 804-812.
10Corduneanu C. Principles of Differential and Integral Equations[M]. Boston, MA: AllynSzamp; Ba- con, 1971.