%0 Journal Article
%A G. S. Rychkov
%T The absence in the equation $P_1(x,y)dx=(y-P_3(x))dy$ of limit cycles surrounding three singular points
%J Differencialʹnye uravneniâ
%D 1984
%P 1906-1910
%V 20
%N 11
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1984_20_11_a7/
%G ru
%F DE_1984_20_11_a7