Nikolskii, M.S. (2001). The Continuity of the Optimal Value of a Functional in Some Optimal Control Problems. Differential Equations 37 (11), 1589-1596. 10.1023/A:1017968816148.
Nikolskii, M.S. (2001). About continuous dependence of minimal value for integral functional in optimal control problems with fixed endpoints and varying duration of process. In: Preprints of the 5th IFAC Symposium on Nonlinear Control Systems, 4-6 July 2001.