@article{MZ_1973__135_171998,
     author = {Egon Scheffold},
     title = {\"Uber den schwachen {Kegel-Spektralradius} und die nichtnegativen {Spektralwerte} positiver {Operatoren.}},
     journal = {Mathematische Zeitschrift},
     pages = {93--110},
     publisher = {mathdoc},
     volume = {135},
     year = {1973},
     zbl = {0267.47003},
     url = {http://geodesic.mathdoc.fr/item/MZ_1973__135_171998/}
}