Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{IM_1966__2_141853, author = {R.A. RANKIN}, title = {Lattice {Subgroups} of {Free} {Congruence} {Groups.}}, journal = {Inventiones mathematicae}, pages = {215--221}, publisher = {mathdoc}, volume = {2}, year = {1966}, zbl = {0146.04105}, url = {http://geodesic.mathdoc.fr/item/IM_1966__2_141853/} }
R.A. RANKIN. Lattice Subgroups of Free Congruence Groups.. Inventiones mathematicae, Tome 2 (1966), pp. 215-221. http://geodesic.mathdoc.fr/item/IM_1966__2_141853/