1. Rouche N., Habets P., and Laloy M., Stability Theory by Lyapunov’s Direct Method, Springer-Verlag, New York, Heidelberg, and Berlin (1977).
2. Barbashin E. A., The Lyapunov Functions [in Russian], Nauka, Moscow (1970).
3. Sell G. R., “Nonautonomous differential equations and topological dynamics. 1 and 2,” Trans. Amer. Math. Soc., 22, 241–283 (1967).
4. Artstein Z., “Topological dynamics of an ordinary differential equation,” J. Differential Equations, 23, 216–223 (1977).
5. Artstein Z., “Topological dynamics of an ordinary differential equation,” J. Differential Equations, 23, 224–243 (1977).