%0 Journal Article
%A I. M. Vul'pe
%T The determination of periodic solutions of nonlinear systems by the averaging method
%J Differencialʹnye uravneniâ
%D 1978
%P 1558-1565
%V 14
%N 9
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1978_14_9_a2/
%G ru
%F DE_1978_14_9_a2