%0 Journal Article
%A K. Krzyżewski
%T Note on approximative derivative
%J Colloquium Mathematicum
%D 1963
%P 281-285
%V 10
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/articles/10.4064/cm-10-2-281-285/
%R 10.4064/cm-10-2-281-285
%G en
%F 10_4064_cm_10_2_281_285