@article{GDZPPN002403331, title = {Non-Euclidean Points in Sphere-like Spaces.}, journal = {Mathematische Zeitschrift}, volume = {105}, year = {1968}, pages = {127-132}, zbl = {0162.27104}, url = {http://dml.mathdoc.fr/item/GDZPPN002403331} }
Koch, Robert J.; Cohen, Haskell. Non-Euclidean Points in Sphere-like Spaces.. Mathematische Zeitschrift, Tome 105 (1968) pp. 127-132. http://gdmltest.u-ga.fr/item/GDZPPN002403331/