@article{02112562,
title = {Ivory's theorem in hyperbolic spaces.},
journal = {Sibirskij Matematicheskij Zhurnal},
volume = {45},
year = {2004},
pages = {946-959},
zbl = {1051.51012},
language = {en},
url = {http://dml.mathdoc.fr/item/02112562}
}
Stachel, Hellmuth; Wallner, Johannes. Ivory's theorem in hyperbolic spaces.. Sibirskij Matematicheskij Zhurnal, Tome 45 (2004) pp. 946-959. http://gdmltest.u-ga.fr/item/02112562/