%0 Journal Article
%A L. V. Hörmander
%T Hypoelliptic differential equations of second order
%J Matematika
%D 1968
%P 88-109
%V 12
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MAT_1968_12_2_a3/
%G ru
%F MAT_1968_12_2_a3