@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/