%0 Journal Article
%A Yu. V. Malyshev
%A V. P. Zakharov
%T Investigation of the existence and convexity of limit cycles by the method of generalized Lyapunov functions
%J Differencialʹnye uravneniâ
%D 1989
%P 212-216
%V 25
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1989_25_2_a4/
%G ru
%F DE_1989_25_2_a4