@article{MZ_1994__216_4_174667,
     author = {Riccardo Salvati Manni},
     title = {Thetanullwerte and stable modular forms for {Hecke} groups.},
     journal = {Mathematische Zeitschrift},
     pages = {529--540},
     publisher = {mathdoc},
     volume = {216},
     number = {4},
     year = {1994},
     zbl = {0814.11029},
     url = {http://geodesic.mathdoc.fr/item/MZ_1994__216_4_174667/}
}