Natascha Esau Evgenija Wetzel Lisa Kleinjohann Bernd Kleinjohann Real-Time Facial Expression Recognition Using a Fuzzy Emotion Model. 1-6 2007 FUZZ-IEEE http://dx.doi.org/10.1109/FUZZY.2007.4295451 conf/fuzzIEEE/2007 db/conf/fuzzIEEE/fuzzIEEE2007.html#EsauWKK07