Thierry Vidal Paolo Liberatore Guest editorial: STAIRS 2002 (http: //stairs2002.univ-lyon1.fr/). 1-2 2004 17 AI Commun. 1 http://iospress.metapress.com/openurl.asp?genre=article&issn=0921-7126&volume=17&issue=1&spage=1 db/journals/aicom/aicom17.html#VidalL04