@article{MAN_1899__52_157936,
     author = {H. Liebmann},
     title = {K\"urzeste und geradeste {Linien} im {M\"obius'-schen} {Nullsystem}},
     journal = {Mathematische Annalen},
     pages = {120--126},
     publisher = {mathdoc},
     volume = {52},
     year = {1899},
     zbl = {30.0588.02},
     url = {http://geodesic.mathdoc.fr/item/MAN_1899__52_157936/}
}