@article{MAN_1899__52_157949,
     author = {Robert Fricke},
     title = {Ueber eine einfache {Gruppe} von 504 {Operationen.}},
     journal = {Mathematische Annalen},
     pages = {321--339},
     publisher = {mathdoc},
     volume = {52},
     year = {1899},
     url = {http://geodesic.mathdoc.fr/item/MAN_1899__52_157949/}
}