%0 Journal Article
%A G. S. Rychkov
%T The limit cycles of the equation $u(x+1)du=(-x+ax^2+bxu+cu+du^2)dx$
%J Differencialʹnye uravneniâ
%D 1972
%P 2257-2259
%V 8
%N 12
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1972_8_12_a22/
%G ru
%F DE_1972_8_12_a22