@article{GDZPPN002102331, title = {Differentiability and rigidity of M\"obius groups.}, journal = {Inventiones mathematicae}, volume = {82}, year = {1985}, pages = {557-578}, zbl = {0564.30033}, url = {http://dml.mathdoc.fr/item/GDZPPN002102331} }
Tukia, P. Differentiability and rigidity of Möbius groups.. Inventiones mathematicae, Tome 82 (1985) pp. 557-578. http://gdmltest.u-ga.fr/item/GDZPPN002102331/