%0 Journal Article %A Miroslav Katětov %T On mapping of countable spaces %J Colloquium Mathematicum %D 1949 %P 30-33 %V 2 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-2-1-30-33/ %R 10.4064/cm-2-1-30-33 %G en %F 10_4064_cm_2_1_30_33