%0 Journal Article
%A S. P. Tokarev
%T The normal form of an analytic system of differential equations in the case of a structurally unstable focus
%J Differencialʹnye uravneniâ
%D 1977
%P 1142-1144
%V 13
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1977_13_6_a24/
%G ru
%F DE_1977_13_6_a24