Ying Dai Yoshitaka Shibata Yasuaki Nakano Koji Hashimoto Recognition of Facial Expressions Based on the Hopfield Memory Model. 133-137 1999 ICMCS, Vol. 2 http://computer.org/conferen/proceed/icmcs/0253/volume%202/02530133abs.htm db/conf/icmcs/icmcs99-2.html#DaiSNH99