@TechReport{JeusfeldStaudt91,
  author =    "Manfred Jeusfeld and Martin Staudt",
  title =     "Query {O}ptimization in {D}eductive {O}bject {B}ases",
  institution = "RWTH Aachen",
  year =      "1991",
  number =    "AIB-26-1991",
  url =       "http://aib.informatik.rwth-aachen.de/1991/1991-26.ps.gz",
}