%0 Journal Article
%A Yu. S. Kolesov
%T Proof of Levin's Half-Period Theorem
%J Differencialʹnye uravneniâ
%D 2005
%P 1125-1127
%V 41
%N 8
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_2005_41_8_a14/
%G ru
%F DE_2005_41_8_a14