@article{DAN_1966_166_2_a12,
     author = {M. M. Baitman},
     title = {Sufficient conditions for optimality},
     journal = {Doklady Akademii Nauk},
     pages = {305--308},
     publisher = {mathdoc},
     volume = {166},
     number = {2},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1966_166_2_a12/}
}