%0 Journal Article
%A G. G. Kazaryan
%T A~characterization of hypoellipticity by estimates from below
%J Trudy Matematicheskogo Instituta imeni V.A. Steklova
%D 1976
%P 162-168
%V 140
%I mathdoc
%U http://geodesic.mathdoc.fr/item/TM_1976_140_a7/
%G ru
%F TM_1976_140_a7