1. Mathematical Methods of Optimal Control;Boltianskii,1961
2. Calculus of Variations and Partial Differential Equations of the First Order—I: Partial Differential Equations of the First Order;Carathéodory,1965
3. Dynamic Programming and the Calculus of Variations;Dreyfus,1965
4. “Variational Methods in Problems of Control and Programming,”;Berkowitz;J. Math. Anal. Appl.,1961
5. “Sufficient Conditions for Optimality and the Justification of the Dynamic Programming Method,”;Boltianskii;J. SIAM Control,1966