1. The theory of optimal processes and the maximum principle;Boltyanskii;Izvest. Akad. Nauk S.S.S.R., Ser. Mat.,1960
2. “Vorlesungen über reelle Funktionen”;Carathéodory,1927
3. Theory of time-optimal processes for linear systems;Gamkrelidze;Izvest. Akad. Nauk S.S.S.R., Ser. Mat.,1958
4. Contributions to the theory of control;Kalman;Bol. soc. mat. mex.,1960
5. The time optimal control problem;La Salle,1960