@article{MAN_1879__15_156855,
     author = {Krey},
     title = {Ueber singul\"are {Tangenten} algebraischer {Fl\"achen}},
     journal = {Mathematische Annalen},
     pages = {211--237},
     publisher = {mathdoc},
     volume = {15},
     year = {1879},
     zbl = {11.0468.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1879__15_156855/}
}