@article{MAN_1929__101_159330,
     author = {W. Fenchel},
     title = {\"Uber {Kr\"ummung} und {Windung} geschlossener {Raumkurven}},
     journal = {Mathematische Annalen},
     pages = {238--252},
     publisher = {mathdoc},
     volume = {101},
     year = {1929},
     zbl = {55.0394.06},
     url = {http://geodesic.mathdoc.fr/item/MAN_1929__101_159330/}
}