@TechReport{Loogen90,
  author =    "Rita Loogen",
  title =     "Stack-based {I}mplementation of {N}arrowing",
  institution = "RWTH Aachen",
  year =      "1990",
  number =    "AIB-04-1990",
  url =       "http://aib.informatik.rwth-aachen.de/1990/1990-04.ps.gz",
}