TY  - JOUR
AU  - El Haial, Abdelillah
AU  - Labbas, Rabah
TI  - On the ellipticity and solvability of an abstract second-order differential equation
JO  - Electronic Journal of Differential Equations
PY  - 2001
VL  - 2001
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/EJDE_2001__2001__a12/
LA  - en
ID  - EJDE_2001__2001__a12
ER  -