%0 Journal Article
%A M. N. Eliseenko
%T Periodic solutions of second-order ordinary differential equations not solved with respect to the derivative
%J Differencialʹnye uravneniâ
%D 1985
%P 1618-1621
%V 21
%N 9
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1985_21_9_a21/
%G ru
%F DE_1985_21_9_a21