@techreport{HoST99b,
  title = "A Description Logic with Transitive and Converse Roles, Role Hierarchies and Qualifying Number Restrictions",
  author = "Ian Horrocks and Ulrike Sattler and Stephan Tobies",
  year = "1999",
  institution = "LuFg Theoretical Computer Science, RWTH Aachen, Germany",
  number = "99-08",
  url = "download/1999/HoST99b.pdf",
}