%0 Journal Article
%A Yu. S. Kolesov
%T Positive periodic solutions of a class of differential equations of second order
%J Doklady Akademii Nauk
%D 1967
%P 264-266
%V 172
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1967_172_2_a3/
%G ru
%F DAN_1967_172_2_a3