@article{AM2_1990__40_1_137357,
     author = {B. Alpers},
     title = {Note on angle-preserving mappings.},
     journal = {Aequationes mathematicae},
     pages = {1--7},
     year = {1990},
     volume = {40},
     number = {1},
     zbl = {0712.51010},
     url = {http://geodesic.mathdoc.fr/item/AM2_1990__40_1_137357/}
}