%0 Journal Article
%A A. Yu. Levin
%T A comparison principle for second-order differential equations
%J Doklady Akademii Nauk
%D 1960
%P 783-786
%V 135
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1960_135_4_a4/
%G ru
%F DAN_1960_135_4_a4