@article{10_4171_ggd_2,
     author = {Adilson A. Berlatto and Said N. Sidki},
     title = {Virtual endomorphisms of nilpotent groups},
     journal = {Groups, geometry, and dynamics},
     pages = {21--46},
     year = {2007},
     volume = {1},
     number = {1},
     doi = {10.4171/ggd/2},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/2/}
}