@article{MZ_1956__66_169617,
     author = {Max Landsberg},
     title = {\"Uber das {Spektrum} symmetrisierbarer {Endomorphismen} in lokalkonvexen {R\"aumen,} insbesondere in {R\"aumen} vom {Typ} (...).},
     journal = {Mathematische Zeitschrift},
     pages = {58--63},
     publisher = {mathdoc},
     volume = {66},
     year = {1956},
     zbl = {0072.13304},
     url = {http://geodesic.mathdoc.fr/item/MZ_1956__66_169617/}
}