%0 Journal Article
%A P. R. Popivanov
%T The solvability and hypoellipticity of differential equations
%J Trudy Matematicheskogo Instituta imeni V.A. Steklova
%D 1974
%V 29
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/RM_1974_29_1_a23/
%G ru
%F RM_1974_29_1_a23