@article{DAN_1990_312_1_a13,
     author = {V. N. Strakhov},
     title = {Variational methods in the theory of linear transformations of},
     journal = {Doklady Akademii Nauk},
     pages = {63--67},
     publisher = {mathdoc},
     volume = {312},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1990_312_1_a13/}
}