@article{AFM_1996_21_2_a2,
     author = {Chun Cao},
     title = {The chordal norm of discrete {M\"obius} groups in several dimensions},
     journal = {Annales Fennici Mathematici},
     pages = {271--287},
     publisher = {mathdoc},
     volume = {21},
     number = {2},
     year = {1996},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AFM_1996_21_2_a2/}
}