@TechReport{Maassen89,
  author =    "Andreas Maassen",
  title =     "Programming with {H}igher {O}rder {F}unctions",
  institution = "RWTH Aachen",
  year =      "1989",
  number =    "AIB-18-1989",
  url =       "http://aib.informatik.rwth-aachen.de/1989/1989-18.ps.gz",
}