%0 Journal Article
%A L. A. Cherkas
%T The absence of limit cycles for a certain differential equation that has a structurally unstable focus
%J Differencialʹnye uravneniâ
%D 1970
%P 779-783
%V 6
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1970_6_5_a1/
%G ru
%F DE_1970_6_5_a1