%0 Journal Article
%A N. A. Lukashevich
%T The isochronism of a center of certain systems of differential equations
%J Differencialʹnye uravneniâ
%D 1965
%P 295-302
%V 1
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1965_1_3_a1/
%G ru
%F DE_1965_1_3_a1