@article{MAN_1873__6_156612,
     author = {Sturm},
     title = {Ueber {Fusspunkt-Curven} und {-Fl\"achen,} {Normalen} und {Normalebenen}},
     journal = {Mathematische Annalen},
     pages = {241--263},
     publisher = {mathdoc},
     volume = {6},
     year = {1873},
     url = {http://geodesic.mathdoc.fr/item/MAN_1873__6_156612/}
}