@article{PORMA_2001__58_4_51502,
     author = {Sharp, R.},
     title = {Sector estimates for {Kleinian} groups.},
     journal = {Portugaliae mathematica},
     pages = {461--471},
     publisher = {mathdoc},
     volume = {58},
     number = {4},
     year = {2001},
     zbl = {1068.20053},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_2001__58_4_51502/}
}