M. L. Gusakova, “Necessary optimality conditions for systems that are not solved with respect to the derivative”, Differ. Uravn., 8:8 (1972), 1498–1500
1971
3.
R. Gabasov, M. L. Gusakova, “A maximum principle for general discrete systems”, Differ. Uravn., 7:9 (1971), 1581–1590