%0 Journal Article
%A A. V. Megretski
%T Frequency criteria for the existence of periodic solutions for systems with integral constraints
%J Differencialʹnye uravneniâ
%D 1990
%P 594-599
%V 26
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1990_26_4_a5/
%G ru
%F DE_1990_26_4_a5