@article{GDZPPN002307480,
title = {Moebius Planes with Locally Euclidean Circles Are Flat.},
journal = {Mathematische Annalen},
volume = {201},
year = {1973},
pages = {149-156},
zbl = {0234.50021},
url = {http://dml.mathdoc.fr/item/GDZPPN002307480}
}
Groh, Hansjoachim. Moebius Planes with Locally Euclidean Circles Are Flat.. Mathematische Annalen, Tome 201 (1973) pp. 149-156. http://gdmltest.u-ga.fr/item/GDZPPN002307480/