Senator Patrick Leahy, Oliver Stone, former French Minister of Culture Jack Lang, Disney Studio chairman Jeffrey Katzenberg, director Milos Forman, filmmaker and Venice fest chief Gillo Pontecorvo, New Line chairman Bob Shaye and director Andy Davis have been added to the list of participants for the International Artists Rights Symposium, April 27-29 at the Hotel Nikko in Beverly Hills.The wide-ranging colloquium has attracted an international roster that will delve into moral, legal and technological advances that are having an impact on filmmakers’ work. In response to recent U.S.-European tensions brought to light by the General Agreement on Tariff and Trade (GATT) initiative, one forum is titled “Finding Possible Resolutions to Differences.” Friday’s “Cultural Identity” forum includes Lang, MPAA president Jack Valenti, American Film Market prez Jonas Rosenfield and filmmaker Costa-Gavras. Director Joe Dante will provide the keynote for the session on emerging digital technologies Thursday. A second panel will focus on creative rights in this burgeoning arena. Participants will include Mark Dippe of Industrial Light and Magic, cinematographer Allen Daviau, Cinesite digital prez Ed Jones and Michael Backes, co-chair of the AFI-Apple Computer Center.