Shogo Nabe Takayuki Kanda Kazuo Hiraki Hiroshi Ishiguro Kiyoshi Kogure Norihiro Hagita Analysis of human behavior to a communication robot in an open field. 234-241 2006 conf/hri/2006 HRI http://doi.acm.org/10.1145/1121241.1121282 db/conf/hri/hri2006.html#NabeKHIKH06