%0 Journal Article
%A O. A. Oleinik
%A E. V. Radkevich
%T Second order equations with nonnegative characteristic form
%J Itogi nauki i tehniki. Seriâ, Matematičeskij analiz
%D 1971
%P 7-252
%V 7
%U http://geodesic.mathdoc.fr/item/INTM_1971_7_a0/
%G ru
%F INTM_1971_7_a0