@TechReport{LutzSattlerWolter-LTCS-01-04,
  author =       {C. Lutz and U. Sattler and F. Wolter},
  title =        {Modal Logic and the two-variable fragment},   
  institution =  {LuFG Theoretical Computer Science, RWTH Aachen},
  year =         2001,
  type =         {LTCS-Report},  
  number =       {LTCS-01-04},
  address =      {Germany},
  note =         {See http://www-lti.informatik.rwth-aachen.de/Forschung/Reports.html.}
}