@article{DAN_1966_169_3_a10,
     author = {A. M. Rubinov},
     title = {Necessary conditions for an extremum and their application to the investigation of certain equations},
     journal = {Doklady Akademii Nauk},
     pages = {533--535},
     publisher = {mathdoc},
     volume = {169},
     number = {3},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1966_169_3_a10/}
}