1. A survey of Liapunov's second method;Antosiewics,1958
2. Prolongations and Stability in Dynamical Systems;Auslander;RIAS Tech. Rept. 63-18,1963
3. On the theory of generalized dynamical systems;Barbashin;Uch. Zap. Moskov. Gos. Univ.,1949
4. On the bang-bang control problem;Bellman;Quart. Appl. Math.,1956
5. Dynamical Systems;Birkhoff,1927