@article{GDZPPN002112051,
title = {Orbit counting for some discrete groups acting on simply connected manifolds with negative curvature.},
journal = {Inventiones mathematicae},
volume = {115},
year = {1994},
pages = {275-302},
zbl = {0804.58009},
url = {http://dml.mathdoc.fr/item/GDZPPN002112051}
}
Pollicott, Mark; Sharp, Richard. Orbit counting for some discrete groups acting on simply connected manifolds with negative curvature.. Inventiones mathematicae, Tome 115 (1994) pp. 275-302. http://gdmltest.u-ga.fr/item/GDZPPN002112051/