@article{1077377958,
author = {Hahn, Kyong T.},
title = {Trigonometry in a hyperbolic space},
journal = {Duke Math. J.},
volume = {35},
number = {1},
year = {1968},
pages = { 739-745},
language = {en},
url = {http://dml.mathdoc.fr/item/1077377958}
}
Hahn, Kyong T. Trigonometry in a hyperbolic space. Duke Math. J., Tome 35 (1968) no. 1, pp. 739-745. http://gdmltest.u-ga.fr/item/1077377958/