@article{10_4171_ggd_247,
     author = {Yves Cornulier},
     title = {Subgroups approximatively of finite index and wreath products},
     journal = {Groups, geometry, and dynamics},
     pages = {775--788},
     year = {2014},
     volume = {8},
     number = {3},
     doi = {10.4171/ggd/247},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/247/}
}