%0 Journal Article
%A Lawrence Corwin
%T Necessary and sufficient conditions for hypoelliptic of certain left invariant operators on nilpotent Lie groups II.
%J Journal für die reine und angewandte Mathematik
%D 1984
%P 139-152
%V 355
%I mathdoc
%U http://geodesic.mathdoc.fr/item/JRAM_1984__355_152690/
%F JRAM_1984__355_152690