@techreport{Horrocks98f,
  title = "A Description Logic with Transitive and Converse Roles and Role Hierarchies",
  author = "I. Horrocks and U. Sattler",
  year = "1998",
  institution = "LuFg Theoretical Computer Science, RWTH Aachen, Germany",
  number = "98-05",
  url = "http://www.comlab.ox.ac.uk/people/ian.horrocks/Publications/download/1998/Horrocks98f.pdf",
}