%0 Journal Article %A H. Toruńczyk %T A simple proof of Hausdorff's theorem on extending metrics %J Fundamenta Mathematicae %D 1972 %P 191-193 %V 77 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/fm-77-2-191-193/ %R 10.4064/fm-77-2-191-193 %G en %F 10_4064_fm_77_2_191_193