@article{GDZPPN002419211,
title = {Upper and Lower Fredholm Spectra II.},
journal = {Mathematische Zeitschrift},
volume = {154},
year = {1977},
pages = {253-256},
zbl = {0393.47001},
url = {http://dml.mathdoc.fr/item/GDZPPN002419211}
}
Harte, Robin; Anthony, Wickstead. Upper and Lower Fredholm Spectra II.. Mathematische Zeitschrift, Tome 154 (1977) pp. 253-256. http://gdmltest.u-ga.fr/item/GDZPPN002419211/