@article{DAN_1987_292_6_a3,
     author = {S. L. Krushkal'},
     title = {A new approach to variational problems of the theory of},
     journal = {Doklady Akademii Nauk},
     pages = {1297--1300},
     publisher = {mathdoc},
     volume = {292},
     number = {6},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1987_292_6_a3/}
}