%0 Journal Article
%A V. A. Kondrat'ev
%A E. M. Landis
%T Semilinear equations of second order with nonnegative characteristic form
%J Matematičeskie zametki
%D 1988
%P 457-468
%V 44
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_1988_44_4_a4/
%G ru
%F MZM_1988_44_4_a4