@article{DAN_1971_201_6_a5,
     author = {V. A. Trenogin},
     title = {Approximations on families of {Banach} spaces and solvability of linear equations},
     journal = {Doklady Akademii Nauk},
     pages = {1288--1291},
     publisher = {mathdoc},
     volume = {201},
     number = {6},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_201_6_a5/}
}