1. The General Problem of Stability of Motion;Lyapunov,1982
2. A survey of Lyapunov's second method;Antosiewicz,1958
3. Recent contributions to Lyapunov's second method;Antosiewicz;Colloques Internationaux sur les Vibrations Forces dans les Systemes Non-linearies,1964
4. Lyapunov Functions;Barbashin,1970