%0 Journal Article
%A L. Hörmander
%T Hypoelliptic differential operators
%J Matematika
%D 1963
%P 66-78
%V 7
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MAT_1963_7_1_a3/
%G ru
%F MAT_1963_7_1_a3