@article{00936955,
title = {On the Margulis constant for Kleinian groups. I.},
journal = {Annales Academiae Scientiarum Fennicae. Mathematica},
volume = {21},
year = {1996},
pages = {439-462},
zbl = {0854.30031},
language = {en},
url = {http://dml.mathdoc.fr/item/00936955}
}
Gehring, F.W.; Martin, G.J. On the Margulis constant for Kleinian groups. I.. Annales Academiae Scientiarum Fennicae. Mathematica, Tome 21 (1996) pp. 439-462. http://gdmltest.u-ga.fr/item/00936955/