%0 Journal Article
%A L. A. Cherkas
%T Two remarks with respect to conditions for a center
%J Differencialʹnye uravneniâ
%D 1981
%P 1709-1712
%V 17
%N 9
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1981_17_9_a26/
%G ru
%F DE_1981_17_9_a26