TY  - JOUR
AU  - Fine, Benjamin
TI  - Congruence Subgroups of the Picard Group
JO  - Canadian journal of mathematics
PY  - 1980
SP  - 1474
EP  - 1481
VL  - 32
IS  - 6
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CJM-1980-116-7/
DO  - 10.4153/CJM-1980-116-7
ID  - 10_4153_CJM_1980_116_7
ER  -