@TechReport{SCI:Cal2004a,
  author =    "S.P. Callahan and M. Ikits and J.L.D. Comba and
              C.T. Silva",
  title =     "Hardware-Assisted Visibility Sorting for
              Unstructured Volume Rendering",
  number =    "UUSCI-2004-003",
  year =      "2004",
  institution = "University of Utah",
  type =      "{SCI} Institute Technical Report",
  month =     "June",
  url =       "http://www.sci.utah.edu/publications/SCITechReports/UUSCI-2004-003.pdf",
}