@article{MAN_1911__70_158502,
     author = {O. Blumenthal},
     title = {Kanalfl\"achen und {Enveloppenfl\"achen.} {(Mit} 1 {Figur} im {Text).}},
     journal = {Mathematische Annalen},
     pages = {377--404},
     publisher = {mathdoc},
     volume = {70},
     year = {1911},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/MAN_1911__70_158502/}
}