@article{MAN_1880__17_156929,
     author = {in Lund. B\"acklund},
     title = {Zur {Theorie} der partiellen {Differentialgleichung} erster {Ordnung}},
     journal = {Mathematische Annalen},
     pages = {285--328},
     year = {1880},
     volume = {17},
     url = {http://geodesic.mathdoc.fr/item/MAN_1880__17_156929/}
}