@article{1102992501, author = {Kay, David C.}, title = {The ptolemaic inequality in Hilbert geometries.}, journal = {Pacific J. Math.}, volume = {23}, number = {3}, year = {1967}, pages = { 293-301}, language = {en}, url = {http://dml.mathdoc.fr/item/1102992501} }
Kay, David C. The ptolemaic inequality in Hilbert geometries.. Pacific J. Math., Tome 23 (1967) no. 3, pp. 293-301. http://gdmltest.u-ga.fr/item/1102992501/