@article{05228042,
title = {Elementary formulas for a hyperbolic tetrahedron.},
journal = {Sibirskij Matematicheskij Zhurnal},
volume = {47},
year = {2006},
pages = {831-841},
zbl = {1150.51305},
language = {en},
url = {http://dml.mathdoc.fr/item/05228042}
}
Mednykh, A.D.; Pashkevich, M.G. Elementary formulas for a hyperbolic tetrahedron.. Sibirskij Matematicheskij Zhurnal, Tome 47 (2006) pp. 831-841. http://gdmltest.u-ga.fr/item/05228042/