@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/