@article{DAN_1987_294_1_a3,
     author = {V. L. Velikin},
     title = {Best approximation in a {Banach} space by a convergent sequence of subspaces of fixed dimension},
     journal = {Doklady Akademii Nauk},
     pages = {23--26},
     publisher = {mathdoc},
     volume = {294},
     number = {1},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1987_294_1_a3/}
}