@article{DAN_1968_181_5_a12,
     author = {V. V. Filippov},
     title = {The preservation of the multiplicity of a basis under a perfect map},
     journal = {Doklady Akademii Nauk},
     pages = {1077--1079},
     publisher = {mathdoc},
     volume = {181},
     number = {5},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_181_5_a12/}
}