@article{CMH_1977__52_139718,
     author = {Olli Lehto},
     title = {Domain constants associated with {Schwarzian} derivative.},
     journal = {Commentarii mathematici Helvetici},
     pages = {603--610},
     year = {1977},
     volume = {52},
     zbl = {0373.30014},
     url = {http://geodesic.mathdoc.fr/item/CMH_1977__52_139718/}
}