@article{CMUC_1967_8_3_a5,
     author = {Kat\v{e}tov, Miroslav},
     title = {A theorem on mappings},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {431--433},
     year = {1967},
     volume = {8},
     number = {3},
     mrnumber = {0229228},
     zbl = {0206.51901},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1967_8_3_a5/}
}