@article{DAN_1967_177_6_a0,
     author = {N. V. Velichko},
     title = {Extension of mappings of toplogical spaces},
     journal = {Doklady Akademii Nauk},
     pages = {1255--1258},
     publisher = {mathdoc},
     volume = {177},
     number = {6},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_177_6_a0/}
}