@article{10_4171_ggd_87,
     author = {Mariya Vorobets and Yaroslav Vorobets},
     title = {On a series of finite automata defining free transformation groups},
     journal = {Groups, geometry, and dynamics},
     pages = {377--405},
     year = {2010},
     volume = {4},
     number = {2},
     doi = {10.4171/ggd/87},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/87/}
}