@TECHREPORT{AmatoS05tr-1, author = {Gianluca Amato and Francesca Scozzari}, title = {Optimality in goal-dependent Analysis of Sharing}, institution = {Dipartimento di Informatica, Universit{\`a} di Pisa}, year = {2005}, number = {TR-05-06}, url = {http://compass2.di.unipi.it/TR/Files/TR-05-06.ps.gz} }