@article{DAN_1971_199_2_a6,
     author = {V. I. Plotnikov},
     title = {Necessary conditions of optimality for control systems of general type},
     journal = {Doklady Akademii Nauk},
     pages = {275--278},
     publisher = {mathdoc},
     volume = {199},
     number = {2},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_199_2_a6/}
}