1. On a certain generalization of the notion of the Bellman function;Petrov;Differentsial'nye Uravneniia,1970
2. The Mathematical Theory of Optimal Processes;Pontriagin,1969
3. On the controllability of autonomous systems;Petrov;Differentsial'nye Uravneniia,1968
4. The solution of a certain problem of controllability;Petrov;Differentsial'nye Uravneniia,1969
5. Functional Analysis in Normed Spaces;Kantorovich,1959