@article{MAN_1961__142_160822,
     author = {G. Ewald},
     title = {Ein {Schlie{\ss}ungssatz} f\"ur {Inzidenz} und {Orthogonalit\"at} in {M\"obiusebenen.}},
     journal = {Mathematische Annalen},
     pages = {1--21},
     publisher = {mathdoc},
     volume = {142},
     year = {1961},
     zbl = {0094.15701},
     url = {http://geodesic.mathdoc.fr/item/MAN_1961__142_160822/}
}