%0 Journal Article
%A V. V. Amel'kin
%T The periodic solutions of a certain nonautonomous system
%J Differencialʹnye uravneniâ
%D 1969
%P 2085-2086
%V 5
%N 11
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1969_5_11_a13/
%G ru
%F DE_1969_5_11_a13