@TechReport{JeusfeldJarke91,
  author =    "Manfred Jeusfeld and Matthias Jarke",
  title =     "From {R}elational to {O}bject-{O}riented {I}ntegrity {S}implification",
  institution = "RWTH Aachen",
  year =      "1991",
  number =    "AIB-19-1991",
  url =       "http://aib.informatik.rwth-aachen.de/1991/1991-19.ps.gz",
}