@article{MAN_1886__26_157195,
     author = {Weltzien},
     title = {Zur {Theorie} der {Doppelpunkte} und {Doppeltangenten} der ebenen rationalen {Curven.}},
     journal = {Mathematische Annalen},
     pages = {516--533},
     publisher = {mathdoc},
     volume = {26},
     year = {1886},
     zbl = {18.0671.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1886__26_157195/}
}