@TechReport{SchuerrWestfechtel92,
  author =    {Andy Sch\"urr and Bernhard Westfechtel},
  title =     "Graphgrammatiken und {G}raphersetzungssysteme",
  institution = "RWTH Aachen",
  year =      "1992",
  number =    "AIB-15-1992",
  url =       "http://aib.informatik.rwth-aachen.de/1992/1992-15.ps.gz",
}