@article{GDZPPN002238136,
title = {The number of elliptic curves over Q with conductor N.},
journal = {Manuscripta mathematica},
volume = {91},
year = {1996},
pages = {95-102},
zbl = {0868.11029},
url = {http://dml.mathdoc.fr/item/GDZPPN002238136}
}
Silverman, Joseph H.; Brumer, Armand. The number of elliptic curves over Q with conductor N.. Manuscripta mathematica, Tome 91 (1996) pp. 95-102. http://gdmltest.u-ga.fr/item/GDZPPN002238136/