@TechReport{SCI:Cal2008c,
  author =    "S.P. Callahan and C.T. Silva",
  title =     "Image-Space Acceleration for Direct Volume
              Rendering of Unstructured Grids using Joint
              Bilateral Upsampling",
  number =    "UUSCI-2008-002",
  year =      "2008",
  institution = "University of Utah",
  type =      "SCI Technical Report",
  url =       "http://www.sci.utah.edu/publications/SCITechReports/UUSCI-2008-002.pdf",
}