@Article{SCI:Fle2011b,
  author =    "P.T. Fletcher and J. Moeller and J. Phillips and
              S. Venkatasubramanian",
  title =     "Horoball hulls and extents in positive definite
              space",
  journal =   "Algorithms and Data Structures",
  volume =    "6844/2011",
  pages =     "386--398",
  year =      "2011",
  series =    "Lecture Notes in Computer Science (LNCS)",
  doi =       "10.1007/978-3-642-22300-6_33",
  url =       "http://www.sci.utah.edu/publications/fletcher11/Fletcher_ADS2011.pdf",
}