@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/