%0 Journal Article
%A L. A. Cherkas
%T The number of limit cycles of a certain second order autonumous system
%J Differencialʹnye uravneniâ
%D 1976
%P 944-946
%V 12
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1976_12_5_a21/
%G ru
%F DE_1976_12_5_a21