@article{GDZPPN001170791,
title = {Approximation du spectre d'un operateur linearie; application aux operateurs differentiels elliptiqes non autoadjoints.},
journal = {Numerische Mathematik},
volume = {19},
year = {1972},
pages = {193-204},
zbl = {0268.65070},
url = {http://dml.mathdoc.fr/item/GDZPPN001170791}
}
Chatelin, F. Approximation du spectre d'un operateur linearie; application aux operateurs differentiels elliptiqes non autoadjoints.. Numerische Mathematik, Tome 19 (1972) pp. 193-204. http://gdmltest.u-ga.fr/item/GDZPPN001170791/