@article{MAN_1935__110_159739,
     author = {H. Seifert},
     title = {\"Uber das {Geschlecht} von {Knoten}},
     journal = {Mathematische Annalen},
     pages = {571--592},
     publisher = {mathdoc},
     volume = {110},
     year = {1935},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/MAN_1935__110_159739/}
}