@TechReport{Geiler91,
  author =    "Guenther Geiler (ed.) Fachgruppe Informatik",
  title =     "Jahresbericht 1990",
  institution = "RWTH Aachen",
  year =      "1991",
  number =    "AIB-01-1991",
  url =       "http://aib.informatik.rwth-aachen.de/1991/1991-01.ps.gz",
}