@TechReport{LutAreHorSat-LTCS-02-04,
  author =       {C. Lutz and C. Areces and I. Horrocks and U. Sattler},
  title =        {Keys, Nominals, and Concrete Domains},
  institution =  {Chair for Automata Theory, Institute for Theoretical
                  Computer Science, Dresden University of Technology},
  year =         2002,
  type =         {LTCS-Report},
  number =       {LTCS-02-04},
  address =      {Germany},
  note =         {See http://lat.inf.tu-dresden.de/research/reports.html.}
}