%0 Journal Article
%A Sokolov,  Maksim S.
%T An abstract approach to some spectral problems of direct sum differential operators
%J Electronic journal of differential equations
%D 2003
%V 2003
%U http://geodesic.mathdoc.fr/item/EJDE_2003__2003__a116/
%G en
%F EJDE_2003__2003__a116