Generating Robot/Agent backchannels during a storytelling experiment. - Sames Al Moubayed; Malek Baklouti; Mohamed Chetouani; Thierry Dutoit; Ammar Mahdhaoui; Jean-Claude Martin; Stanislav Ondás; Catherine Pelachaud; Jérôme Urbain; Mehmet Yilmaz (ICRA, 2009)