@article{10_4171_ggd_152,
     author = {Kingshook Biswas and Mahan Mj},
     title = {Pattern rigidity in hyperbolic spaces:  duality and {PD} subgroups},
     journal = {Groups, geometry, and dynamics},
     pages = {97--123},
     year = {2012},
     volume = {6},
     number = {1},
     doi = {10.4171/ggd/152},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/152/}
}