@article{DAN_1968_182_4_a1,
     author = {V. V. Velichenko},
     title = {On sufficient conditions for optimality in the maximum principle},
     journal = {Doklady Akademii Nauk},
     pages = {747--749},
     publisher = {mathdoc},
     volume = {182},
     number = {4},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_182_4_a1/}
}