%0 Journal Article
%A Yu. V. Egorov
%A V. A. Kondrat'ev
%T On the negative spectrum of an elliptic operator
%J Sbornik. Mathematics
%D 1991
%P 155-177
%V 69
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SM_1991_69_1_a9/
%G en
%F SM_1991_69_1_a9