@article{JRAM_1925__154_149558,
     author = {Bernhard von Ludwig},
     title = {Die nat\"urliche {Verallgemeinerung} des {Jacobischen} {Umkehrproblems.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {50--62},
     publisher = {mathdoc},
     volume = {154},
     year = {1925},
     zbl = {50.0270.01},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1925__154_149558/}
}