@article{MZ_1939__44_168832,
     author = {J., Heinhold},
     title = {Verallgemeinerung und {Versch\"arfung} eines {Minkowskischen} {Satzes}},
     journal = {Mathematische Zeitschrift},
     pages = {659--688},
     year = {1939},
     volume = {44},
     zbl = {65.0174.03},
     url = {http://geodesic.mathdoc.fr/item/MZ_1939__44_168832/}
}