%0 Journal Article
%A L. A. Cherkas
%T Conditions for the center for a certain equation
%J Differencialʹnye uravneniâ
%D 1977
%P 271-275
%V 13
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1977_13_2_a4/
%G ru
%F DE_1977_13_2_a4