@article{JLT_2007_17_4_JLT_2007_17_4_a6,
     author = {E. Barbieri and A. Cavicchioli and F. Spaggiari },
     title = {A {Generalization} of {Helling-Kim-Mennicke} {Groups} and {Manifolds}},
     journal = {Journal of Lie theory},
     pages = {857--867},
     publisher = {mathdoc},
     volume = {17},
     number = {4},
     year = {2007},
     url = {http://geodesic.mathdoc.fr/item/JLT_2007_17_4_JLT_2007_17_4_a6/}
}