%0 Journal Article
%A N. P. Morozov
%T Periodic solutions of the equation $\ddot x+\lambda f(x,\dot x)\dot x+x=0$
%J Differencialʹnye uravneniâ
%D 1988
%P 1826-1828
%V 24
%N 10
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1988_24_10_a24/
%G ru
%F DE_1988_24_10_a24