%0 Journal Article
%A Yu. A. Semenov
%T On the spectral theory of second-order elliptic differential operators
%J Sbornik. Mathematics
%D 1987
%P 221-247
%V 56
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SM_1987_56_1_a13/
%G en
%F SM_1987_56_1_a13