@article{JRAM_1953__191_150226,
     author = {Horst Schubert},
     title = {Zur {Differenzierbarkeit} der {Abbildungen} von {Punktmengen} des euklidischen {Raumes.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {1--12},
     publisher = {mathdoc},
     volume = {191},
     year = {1953},
     zbl = {0050.06101},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1953__191_150226/}
}