@article{IM_1975__30_142347,
     author = {Eberhard Freitag},
     title = {Holomorphe {Differentialformen} zu {Kongruenzgruppen} der {Siegelschen} {Modulgruppe.}},
     journal = {Inventiones mathematicae},
     pages = {181--196},
     publisher = {mathdoc},
     volume = {30},
     year = {1975},
     zbl = {0314.32017},
     url = {http://geodesic.mathdoc.fr/item/IM_1975__30_142347/}
}