%0 Journal Article
%A A. A. Zevin
%T Estimates for periodic solutions of systems of second-order nonlinear differential equations
%J Differencialʹnye uravneniâ
%D 1985
%P 932-937
%V 21
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1985_21_6_a1/
%G ru
%F DE_1985_21_6_a1