Hiroaki Kawashima Takeshi Nishikawa Takashi Matsuyama Visual filler: facilitating smooth turn-taking in video conferencing with transmission delay. 3585-3590 2008 CHI Extended Abstracts http://doi.acm.org/10.1145/1358628.1358895 conf/chi/2008a db/conf/chi/chi2008a.html#KawashimaNM08