%0 Journal Article
%A A. Yu. Veretennikov
%T Conditions for hypo-ellipticity and estimates for the rate of
%J Doklady Akademii Nauk
%D 1989
%P 524-526
%V 307
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1989_307_3_a1/
%G ru
%F DAN_1989_307_3_a1