@article{ELMA_1955__10_140613,
     author = {R. Sauer},
     title = {Elementargeometrische {Modelle} zur {Differentialgeometrie.} {(Fortsetzung).}},
     journal = {Elemente der Mathematik},
     pages = {4--11},
     publisher = {mathdoc},
     volume = {10},
     year = {1955},
     zbl = {0064.15901},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1955__10_140613/}
}