@article{MZ_1932__34_168336,
     author = {J., Lense},
     title = {\"Uber die {Ableitungsgleichungen} der ametrischen {Mannigfaltigkeiten}},
     journal = {Mathematische Zeitschrift},
     pages = {721--736},
     publisher = {mathdoc},
     volume = {34},
     year = {1932},
     zbl = {58.0783.01},
     url = {http://geodesic.mathdoc.fr/item/MZ_1932__34_168336/}
}