@article{MAN_1904__58_158130,
     author = {P. Wernicke},
     title = {\"Uber den kartographischen {Vierfarbensatz.} {(Mit} 23 {Figuren} im {Text)}},
     journal = {Mathematische Annalen},
     pages = {413--426},
     publisher = {mathdoc},
     volume = {58},
     year = {1904},
     zbl = {35.0511.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1904__58_158130/}
}