@article{IM_1989__97_2_143708,
     author = {P. Tukia},
     title = {A rigidity theorem for {M\"obius} groups.},
     journal = {Inventiones mathematicae},
     pages = {405--432},
     publisher = {mathdoc},
     volume = {97},
     number = {2},
     year = {1989},
     zbl = {0674.30038},
     url = {http://geodesic.mathdoc.fr/item/IM_1989__97_2_143708/}
}