Simona Perri Nicola Leone Parametric connectives in Disjunctive Logic Programming. 63-74 2004 17 AI Commun. 2 http://iospress.metapress.com/openurl.asp?genre=article&issn=0921-7126&volume=17&issue=2&spage=63 db/journals/aicom/aicom17.html#PerriL04