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@article{DAN_1972_202_6_a7, author = {A. V. Ostrovsky}, title = {On $k$-covering mappings of separable metric spaces}, journal = {Doklady Akademii Nauk}, pages = {1271--1273}, publisher = {mathdoc}, volume = {202}, number = {6}, year = {1972}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1972_202_6_a7/} }
A. V. Ostrovsky. On $k$-covering mappings of separable metric spaces. Doklady Akademii Nauk, Tome 202 (1972) no. 6, pp. 1271-1273. http://geodesic.mathdoc.fr/item/DAN_1972_202_6_a7/