@article{MAN_1973__201_162381,
     author = {Hansjoachim Groh},
     title = {Moebius {Planes} with {Locally} {Euclidean} {Circles} {Are} {Flat.}},
     journal = {Mathematische Annalen},
     pages = {149--156},
     publisher = {mathdoc},
     volume = {201},
     year = {1973},
     zbl = {0234.50021},
     url = {http://geodesic.mathdoc.fr/item/MAN_1973__201_162381/}
}