@article{CMH_1973__48_139559,
     author = {A. Borel and J-P. Serre},
     title = {Corners and {Arithmetic} {Groups}},
     journal = {Commentarii mathematici Helvetici},
     pages = {436--483},
     publisher = {mathdoc},
     volume = {48},
     year = {1973},
     zbl = {0274.22011},
     url = {http://geodesic.mathdoc.fr/item/CMH_1973__48_139559/}
}