@article{01208018, title = {Pappus' theorem for ring-geometries.}, journal = {Beitr\"age zur Algebra und Geometrie}, volume = {39}, year = {1998}, pages = {461-466}, zbl = {0918.51002}, language = {en}, url = {http://dml.mathdoc.fr/item/01208018} }
Pfeiffer, Thorsten. Pappus' theorem for ring-geometries.. Beiträge zur Algebra und Geometrie, Tome 39 (1998) pp. 461-466. http://gdmltest.u-ga.fr/item/01208018/