@article{MZ_1977__154_172530,
     author = {Robin Harte and Wickstead Anthony},
     title = {Upper and {Lower} {Fredholm} {Spectra} {II.}},
     journal = {Mathematische Zeitschrift},
     pages = {253--256},
     publisher = {mathdoc},
     volume = {154},
     year = {1977},
     zbl = {0393.47001},
     url = {http://geodesic.mathdoc.fr/item/MZ_1977__154_172530/}
}