@TechReport{SCI:Wal2006a,
  author =    "I. Wald and V. Havran",
  title =     "On building fast kd-Trees for Ray Tracing, and on
              doing that in O(N log N)",
  number =    "UUSCI-2006-009",
  year =      "2006",
  institution = "University of Utah",
  type =      "{SCI} Institute Technical Report",
  keywords =  "rtcenter",
  url =       "http://www.sci.utah.edu/publications/SCITechReports/UUSCI-2006-009.pdf",
}