1. Extremum conditions of functionals;Lyusternik;Matem. Sb.,1934
2. Theory of extremal problems;Yoffe,1974
3. Optimal control;Alekseyev,1979
4. Problems on an extremum when there are constraints;Dubovitskii;Zh. vychisl. Mat. mat. Fiz.,1965
5. Necessary extremum conditions;Pshenichnyi,1969