@article{ZVMMF_1967_7_1_a3,
     author = {V. F. Dem'yanov},
     title = {A non-linear extremal problem},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {33--51},
     publisher = {mathdoc},
     volume = {7},
     number = {1},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1967_7_1_a3/}
}