%0 Journal Article
%A S. M. Nikol'skii
%T The preservation of class under a differentiable mapping
%J Trudy Matematicheskogo Instituta imeni V.A. Steklova
%D 1971
%P 327-336
%V 112
%I mathdoc
%U http://geodesic.mathdoc.fr/item/TM_1971_112_a20/
%G ru
%F TM_1971_112_a20