%0 Journal Article
%A N. G. Bulgakov
%T On the existence of periodic solutions to nonlinear systems
%J Differencialʹnye uravneniâ
%D 1972
%P 1876-1877
%V 8
%N 10
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1972_8_10_a17/
%G ru
%F DE_1972_8_10_a17