@article{01645677,
title = {On the ellipticity and solvability of an abstract second-order differential equation.},
journal = {Electronic Journal of Differential Equations (EJDE) [electronic only]},
volume = {2001},
year = {2001},
zbl = {0996.34046},
language = {en},
url = {http://dml.mathdoc.fr/item/01645677}
}
El Haial, Abdelillah; Labbas, Rabah. On the ellipticity and solvability of an abstract second-order differential equation.. Electronic Journal of Differential Equations (EJDE) [electronic only], Tome 2001 (2001) . http://gdmltest.u-ga.fr/item/01645677/