@article{10_4171_ggd_220,
     author = {Darlan Gir\~ao},
     title = {Rank gradient in co-final towers of certain {Kleinian} groups},
     journal = {Groups, geometry, and dynamics},
     pages = {143--155},
     year = {2014},
     volume = {8},
     number = {1},
     doi = {10.4171/ggd/220},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/220/}
}