%0 Journal Article
%A N. M. Isakov
%T $C^r$-property and approximately differentiable functions
%J Matematičeskie zametki
%D 1991
%P 59-62
%V 49
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_1991_49_6_a6/
%G ru
%F MZM_1991_49_6_a6