@article{MZ_1955__63_169539, author = {Hans Freudenthal}, title = {Neuere {Fassungen} des {Riemann-Helmholtz-Lieschen} {Raumproblems.}}, journal = {Mathematische Zeitschrift}, pages = {374--405}, publisher = {mathdoc}, volume = {63}, year = {1955}, zbl = {0074.36103}, url = {http://geodesic.mathdoc.fr/item/MZ_1955__63_169539/} }