Bilge Mutlu Toshiyuki Shiwa Takayuki Kanda Hiroshi Ishiguro Norihiro Hagita Footing in human-robot conversations: how robots might shape participant roles using gaze cues. 61-68 2009 HRI http://doi.acm.org/10.1145/1514095.1514109 conf/hri/2009 db/conf/hri/hri2009.html#MutluSKIH09