@article{GDZPPN00218205X,
title = {Density and maximality of arithmetic subgroups.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {222},
year = {1966},
pages = {78-89},
zbl = {0158.03105},
url = {http://dml.mathdoc.fr/item/GDZPPN00218205X}
}
Borel, Arnold. Density and maximality of arithmetic subgroups.. Journal für die reine und angewandte Mathematik, Tome 222 (1966) pp. 78-89. http://gdmltest.u-ga.fr/item/GDZPPN00218205X/