@article{GDZPPN00222089X, title = {\"Uber Tangentialk\"orper der Kugel.}, journal = {Manuscripta mathematica}, volume = {22}, year = {1977}, pages = {269-278}, zbl = {0383.52004}, url = {http://dml.mathdoc.fr/item/GDZPPN00222089X} }
Schneider, Rolf. Über Tangentialkörper der Kugel.. Manuscripta mathematica, Tome 22 (1977) pp. 269-278. http://gdmltest.u-ga.fr/item/GDZPPN00222089X/