APA (7th ed.) Citation

Zhu, Y. (2001). Facial expression recognition using hidden markov model.

Chicago Style (17th ed.) Citation

Zhu, Yi. Facial Expression Recognition Using Hidden Markov Model. 2001.

MLA (8th ed.) Citation

Zhu, Yi. Facial Expression Recognition Using Hidden Markov Model. 2001.

Warning: These citations may not always be 100% accurate.