@article{MZ_1921__10_167630,
     author = {H., Falckenberg},
     title = {Ableitung der },
     journal = {Mathematische Zeitschrift},
     pages = {17--38},
     publisher = {mathdoc},
     volume = {10},
     year = {1921},
     zbl = {48.0452.01},
     url = {http://geodesic.mathdoc.fr/item/MZ_1921__10_167630/}
}