@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/