%0 Journal Article
%A V. I. Mironenko
%T Simple systems and periodic solutions of differential equations
%J Differencialʹnye uravneniâ
%D 1989
%P 2109-2114
%V 25
%N 12
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1989_25_12_a9/
%G ru
%F DE_1989_25_12_a9