@article{MAN_1923__89_158991,
     author = {H. Mohrmann},
     title = {Die {Fl\"achen} vierter {Ordnung} mit gewundener {Doppelkurve}},
     journal = {Mathematische Annalen},
     pages = {1--31},
     publisher = {mathdoc},
     volume = {89},
     year = {1923},
     zbl = {49.0477.04},
     url = {http://geodesic.mathdoc.fr/item/MAN_1923__89_158991/}
}