@ARTICLE{MeseguerEtAl06,
  author =       {Jos{\'e} Meseguer and Miguel Palomino and
                  Narciso Mart{\'\i}-Oliet},
  title =        {Equational Abstractions},
  journal =      {Theoretical Computer Science},
  year =         2008,
  volume =       403,
  number =       {2-3},
  pages =        {239-264}
}