@article{MZ_1988__200_3_174001,
     author = {Bruno Zimmermann and Michel Boileau},
     title = {The ?-orbifold {Group} of a {Link.}},
     journal = {Mathematische Zeitschrift},
     pages = {187--208},
     year = {1988},
     volume = {200},
     number = {3},
     zbl = {0663.57006},
     url = {http://geodesic.mathdoc.fr/item/MZ_1988__200_3_174001/}
}