@article{GDZPPN002431289,
title = {The Schur Multiplicator of SL(2, Z/mZ) and the Congruence Subgroup Property.},
journal = {Mathematische Zeitschrift},
volume = {192},
year = {1986},
pages = {23-42},
zbl = {0581.20050},
url = {http://dml.mathdoc.fr/item/GDZPPN002431289}
}
Beyl, F. Rudolf. The Schur Multiplicator of SL(2, Z/mZ) and the Congruence Subgroup Property.. Mathematische Zeitschrift, Tome 192 (1986) pp. 23-42. http://gdmltest.u-ga.fr/item/GDZPPN002431289/