@article{10_4171_ggd_42,
     author = {Laurent Bartholdi and Volodymyr V. Nekrashevych},
     title = {Iterated monodromy groups of quadratic polynomials, {I}},
     journal = {Groups, geometry, and dynamics},
     pages = {309--336},
     year = {2008},
     volume = {2},
     number = {3},
     doi = {10.4171/ggd/42},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/42/}
}