1. A. B. Vasil'eva, ?On a question about the solutions, close to discontinuous ones, in a system with a small parameter for derivatives of conditionally stable type,? Differents. Uravn.,8, No. 9, 1560?1568 (1972).
2. A. B. Vasil'eva and V. F. Butuzov, Asymptotic Expansions of Solutions of Singularly Perturbed Equations [in Russian], Nauka, Moscow (1973).
3. A. B. Vasil'eva, V. A. Tupchiev, and A. N. Yarkin, ?Periodic solutions, close to discontinuous ones, of systems of differential equations with a small parameter for derivatives,? in: Proceedings of the 5th International Conference on Nonlinear Oscillations [in Russian], Vol. 1, Izd. Inst. Mat. Akad. Nauk Ukr. SSR, Kiev (1970), pp. 149?157.
4. G. Nikolis and I. Prigogine, Self-Organization in Nonequilibrium Systems, Wiley, New York (1977).