%0 Journal Article
%A E. D. Zhitelzeif
%T A test for the existence of a periodic solution of the Li\'enard equation
%J Differencialʹnye uravneniâ
%D 1970
%P 1127-1130
%V 6
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1970_6_6_a20/
%G ru
%F DE_1970_6_6_a20