@UNPUBLISHED{MartiOlietEtAl03-journal,
  author =      {Jos{\'e} Meseguer and
                  Miguel Palomino and Narciso Mart{\'\i}-Oliet},
  title =      {Algebraic Simulations},
  year =      2007,
  note =         {Submitted. \url{http://maude.sip.ucm.es/~miguelpt/}}
}