@article{DAN_1973_213_2_a0,
     author = {V. G. Boltyanskii and I. S. Chebotaru},
     title = {Necessary conditions in a minimax problem},
     journal = {Doklady Akademii Nauk},
     pages = {257--260},
     publisher = {mathdoc},
     volume = {213},
     number = {2},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_213_2_a0/}
}