@article{10_4153_CMB_1994_030_1,
     author = {Fine, Benjamin},
     title = {Trace {Classes} and {Quadratic} {Forms} in the {Modular} {Group}},
     journal = {Canadian mathematical bulletin},
     pages = {202--212},
     year = {1994},
     volume = {37},
     number = {2},
     doi = {10.4153/CMB-1994-030-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1994-030-1/}
}