%0 Journal Article
%A S. P. Tokarev
%T Smooth equivalence of systems of differential equations on the plane in the case of a structurally unstable focus
%J Differencialʹnye uravneniâ
%D 1977
%P 892-897
%V 13
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1977_13_5_a11/
%G ru
%F DE_1977_13_5_a11