@article{CMH_1931__3_138548,
     author = {Arnold Emch},
     title = {Ueber die {Abbildung} projektiver {R\"aume.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {1--11},
     year = {1931},
     volume = {3},
     zbl = {0001.29101},
     url = {http://geodesic.mathdoc.fr/item/CMH_1931__3_138548/}
}