@article{MAN_1903__56_158075,
     author = {Otto Blumenthal},
     title = {\"Uber {Modulfunktionen} von mehreren {Ver\"anderlichen.} {(Erste} {H\"alfte)}},
     journal = {Mathematische Annalen},
     pages = {509--548},
     publisher = {mathdoc},
     volume = {56},
     year = {1903},
     zbl = {34.0466.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1903__56_158075/}
}