@article{10_4171_ggd_122,
     author = {Cormac Walsh},
     title = {The action of a nilpotent group on its horofunction boundary has finite orbits},
     journal = {Groups, geometry, and dynamics},
     pages = {189--206},
     year = {2011},
     volume = {5},
     number = {1},
     doi = {10.4171/ggd/122},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/122/}
}