1. M. A. Aizerman, “On a Problem Concerning Stability in “Large” of Dynamic Systems,” Usp. Mat. Nauk 4(4), 186–188 (1949).
2. A. M. Letov, Stability of Nonlinear Control Systems (GTTI, Moscow, 1955) [in Russian].
3. M. A. Aizerman and F. R. Gantmakher, Absolute Stability of Control Systems (Akad. Nauk SSSR, Moscow, 1963) [in Russian].
4. S. L. Lefschetz, Stability of Nonlinear Control Systems (Academic, New York, London, 1965).
5. A. F. Filippov, Differential Equations with Different Right Sides (Nauka, Moscow, 1985) [in Russian].