@TechReport{HorrocksTobies-LTCS-99-14,
  author = 	 {I. Horrocks and S. Tobies},
  title = 	 {Optimisation of Terminological Reasoning},
  institution =  {LuFG Theoretical Computer Science, RWTH Aachen},
  year = 	 1999,
 type           = {LTCS-Report},
  number =	 {LTCS-99-14},
  note = {See http://www-lti.informatik.rwth-aachen.de/Forschung/Reports.html},
  keywords = { Modal Logic, Description Logic, Reasoning, Optimization }
}