@article{MAN_1966__166_161441,
     author = {O. Perron},
     title = {Spiegelungen in der hyperbolischen {Ebene.}},
     journal = {Mathematische Annalen},
     pages = {8--18},
     publisher = {mathdoc},
     volume = {166},
     year = {1966},
     zbl = {0141.18101},
     url = {http://geodesic.mathdoc.fr/item/MAN_1966__166_161441/}
}