@TechReport{BasagniB95tr,
  AUTHOR	= {Basagni, S. and P. Boldi},
  TITLE		= {Causal Equivalence and Congruence between Stable Event
		  Structure},
  NUMBER	= {RI-DSI-147-95},
  INSTITUTION	= {Dipartimento di Scienze dell'Informazione},
  ADDRESS	= {Universit\`{a} di Milano},
  YEAR		= 1995
}