Alberto Pettorossi Maurizio Proietti Preface: Program Transformation: Theoretical Foundations and Basic Techniques. Part 2. 2006 69 Fundam. Inform. 1-2 http://iospress.metapress.com/openurl.asp?genre=article&issn=0169-2968&volume=69&issue=1&spage=v db/journals/fuin/fuin69.html#PettorossiP06