%0 Journal Article
%A Qihong Fan
%A M.W. Wong
%T A characterization of some non-elliptic pseudo-differential operators as Fredholm operators.
%J Forum mathematicum
%D 1997
%P 17-28
%V 9
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/FORUM_1997__9_2_141791/
%F FORUM_1997__9_2_141791