@article{02216000,
title = {Characterization, spectral invariance and the Fredholm property of multi-quasi-elliptic operators.},
journal = {Rendiconti del Seminario Matematico},
volume = {59},
year = {2001},
pages = {229-242},
zbl = {1072.47521},
language = {en},
url = {http://dml.mathdoc.fr/item/02216000}
}
Schrohe, E.; Boggiatto, P. Characterization, spectral invariance and the Fredholm property of multi-quasi-elliptic operators.. Rendiconti del Seminario Matematico, Tome 59 (2001) pp. 229-242. http://gdmltest.u-ga.fr/item/02216000/