@techReport{BruRC101,
   author =      {Kai Br\"unnler},
   title =       {Two Restrictions on Contraction},
   institution = {Technische Universit\"at Dresden},
   year =        2002,
   number =      {WV-02-04},
   note =        {to appear in Logic Journal of the Interest Group in Pure and 
                  Applied Logics}
}