Zsófia Ruttkay Claire Dormann Han Noot Evaluating ECAs - What, how and why? 2004 Evaluating Embodied Conversational Agents http://drops.dagstuhl.de/opus/volltexte/2006/586 conf/dagstuhl/2004P4121 db/conf/dagstuhl/P4121.html#RuttkayDN04