@article{GDZPPN002104148,
title = {Pinching constants for hyperbolic manifolds.},
journal = {Inventiones mathematicae},
volume = {88},
year = {1987},
pages = {1-12},
zbl = {0646.53037},
url = {http://dml.mathdoc.fr/item/GDZPPN002104148}
}
Gromov, M.; Thurston, W. Pinching constants for hyperbolic manifolds.. Inventiones mathematicae, Tome 88 (1987) pp. 1-12. http://gdmltest.u-ga.fr/item/GDZPPN002104148/