%0 Journal Article
%A El Haial,  Abdelillah
%A Labbas,  Rabah
%T On the ellipticity and solvability of an abstract second-order differential equation
%J Electronic journal of differential equations
%D 2001
%V 2001
%U http://geodesic.mathdoc.fr/item/EJDE_2001__2001__a90/
%G en
%F EJDE_2001__2001__a90