@article{GDZPPN002050641, title = {Somengeometrie und Nicht-Euklidische Gemetrie.}, journal = {Commentarii mathematici Helvetici}, volume = {1}, year = {1929}, pages = {42-63}, language = {de}, url = {http://dml.mathdoc.fr/item/GDZPPN002050641} }
Benteli, W. Somengeometrie und Nicht-Euklidische Gemetrie.. Commentarii mathematici Helvetici, Tome 1 (1929) pp. 42-63. http://gdmltest.u-ga.fr/item/GDZPPN002050641/