@TechReport{CluetMoerkotte95,
  author =    "Sophie Cluet and Guido Moerkotte",
  title =     "Nested {Q}ueries in {O}bject {B}ases",
  institution = "RWTH Aachen",
  year =      "1995",
  number =    "AIB-06-1995",
  url =       "http://aib.informatik.rwth-aachen.de/1995/1995-06.ps.gz",
}