@article{GDZPPN002201631,
title = {Genera of congruence subgroups in Q-quaternion algebras.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {346},
year = {1984},
pages = {66-112},
zbl = {0531.10028},
url = {http://dml.mathdoc.fr/item/GDZPPN002201631}
}
Cox, David A.; Parry, Walter R. Genera of congruence subgroups in Q-quaternion algebras.. Journal für die reine und angewandte Mathematik, Tome 346 (1984) pp. 66-112. http://gdmltest.u-ga.fr/item/GDZPPN002201631/