@misc{MZ_1963__81_170125,
     title = {1. {Grundlegende} {Definitionen.}},
     journal = {Mathematische Zeitschrift},
     pages = {4--6},
     year = {1963},
     volume = {81},
     url = {http://geodesic.mathdoc.fr/item/MZ_1963__81_170125/}
}