%0 Journal Article
%A M. V. Dolov
%T Limit cycles in the case of the center
%J Differencialʹnye uravneniâ
%D 1972
%P 1691-1692
%V 8
%N 9
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1972_8_9_a18/
%G ru
%F DE_1972_8_9_a18