%0 Journal Article
%A E. V. Radkevich
%T The smoothness of solutions of the first boundary value problem for second order differential equations with a~non-negative characteristic form
%J Trudy Matematicheskogo Instituta imeni V.A. Steklova
%D 1969
%V 24
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/RM_1969_24_3_a15/
%G ru
%F RM_1969_24_3_a15