@TECHREPORT{AmatoS05tr-2,
  author = {Gianluca Amato and Francesca Scozzari},
  title = {On abstract unification for variable aliasing},
  institution =  {Dipartimento di Informatica, Universit{\`a} di Pisa},
  year = {2005},
  number = {TR-05-08},
  url = {http://compass2.di.unipi.it/TR/Files/TR-05-08.ps.gz}
}