@article{1250523378,
author = {Chuman, Yasuhiro},
title = {Generators and relations of $\Gamma\_0(N)$},
journal = {J. Math. Kyoto Univ.},
volume = {13},
number = {3},
year = {1973},
pages = { 381-390},
language = {en},
url = {http://dml.mathdoc.fr/item/1250523378}
}
Chuman, Yasuhiro. Generators and relations of $\Gamma_0(N)$. J. Math. Kyoto Univ., Tome 13 (1973) no. 3, pp. 381-390. http://gdmltest.u-ga.fr/item/1250523378/