Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{RCM_1968__2_181554, author = {N. Allan}, title = {Some non-maximal arithmetic groups}, journal = {Revista colombiana de matematicas}, pages = {21--28}, publisher = {mathdoc}, volume = {2}, year = {1968}, zbl = {0184.24403}, url = {http://geodesic.mathdoc.fr/item/RCM_1968__2_181554/} }
N. Allan. Some non-maximal arithmetic groups. Revista colombiana de matematicas, Tome 2 (1968), pp. 21-28. http://geodesic.mathdoc.fr/item/RCM_1968__2_181554/