@article{MAN_1941__118_160104,
     author = {H. MAASS},
     title = {Theorie der {Poincar\'eschen} {Reihen} zu den hyperbolischen {Fixpunktsystemen} der {Hilbertschen} {Modulgruppe}},
     journal = {Mathematische Annalen},
     pages = {518--543},
     publisher = {mathdoc},
     volume = {118},
     year = {1941},
     zbl = {68.0171.03},
     url = {http://geodesic.mathdoc.fr/item/MAN_1941__118_160104/}
}