@TechReport{HoSat98,
  author = 	 {Horrocks, I. and Sattler, U.},
  title = 	 {A Description Logic with Transitive and Converse Roles and Role Hierarchies},
  institution =  {LuFg Theoretical Computer Science, RWTH Aachen, Germany},
  year = 	 1998,
 type           = {LTCS-Report},
  number =	 {LTCS-98-05}
}