On the Existence of Solutions to Differential Inclusions with Nonconvex Right-Hand Sides. - Mikhail Ivanov Krastanov; N. K. Ribarska; Ts. Y. Tsachev (SIAM J. Optim., 2007)

A Pontryagin Maximum Principle for Infinite-Dimensional Problems. - Mikhail Ivanov Krastanov; N. K. Ribarska; Ts. Y. Tsachev (SIAM J. Control. Optim., 2011)