@techreport{Wyvill:1987:ISR,
  number = {1/1/87},
  optnote = {},
  author = {Geoff Wyvill and Alistair Ward and Tim Brown},
  optkey = {},
  optannote = {},
  opttype = {},
  localfile = {papers/Wyvill.1987.ISR.pdf},
  address = {New Zealand},
  title = {{I}tem 15 -- {S}ketches by {R}ay {T}racing},
  optmonth = {},
  institution = {Department of Computer Science, University of Otago},
  year = {1987},
}