Jesse Hoey James J. Little Decision Theoretic Modeling of Human Facial Displays. 26-38 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3023&spage=26 2004 conf/eccv/2004-3 ECCV (3) db/conf/eccv/eccv2004-3.html#HoeyL04