%0 Journal Article
%A V. A. Pliss
%T The existence of periodic solutions of certain non-linear systems
%J Doklady Akademii Nauk
%D 1961
%P 1060-1062
%V 137
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1961_137_5_a14/
%G ru
%F DAN_1961_137_5_a14