1. A. N. Sharkovskiî, Yu. L. Maîstrenko, and E. Yu. Romanenko, Difference Equations and Their Applications [in Russian], Naukova Dumka, Kiev (1981).
2. A. S. Dmitriev and V. Ya. Kislov, Stochastic Oscillations in Radio Engineering [in Russian], Nauka, Moscow (1989).
3. S. A. Kashchenko, “An application of the normalization method to studying the dynamics of a difference-differential equation with a small factor multiplying the derivative,” Differentsial'nye Uravneniya,25, No. 8, 1448–1450 (1989).
4. S. A. Kashchenko, “Normalization in the systems with small diffusion,” Internat. J. Bifur. Chaos Appl. Sci. Engrg.,6, No. 6, 1093–1109 (1996).
5. T. S. Akhromeeva, S. P. Kurdyumov, G. G. Malinetskiî, and A. A. Samarskiî, Nonstationary Structures and Diffusion Chaos [in Russian], Nauka, Moscow (1992).