@TechReport{BoerstlerZuendorf91,
  author =    {J\"urgen B\"orstler and Albert Z\"undorf},
  title =     "Revisiting extensions to {M}odula-2 to support reusability",
  institution = "RWTH Aachen",
  year =      "1991",
  number =    "AIB-15-1991",
  url =       "http://aib.informatik.rwth-aachen.de/1991/1991-15.ps.gz",
}