%0 Journal Article
%A E. V. Radkevich
%T A priori estimates and hypoelliptic operators with multiple characteristics
%J Doklady Akademii Nauk
%D 1969
%P 274-277
%V 187
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1969_187_2_a10/
%G ru
%F DAN_1969_187_2_a10