Ekman, P. Duchenne and facial expression of emotion: Paul Ekman. The mechanism of human facial expression.(2003).
Chicago-viite (17. p.)Ekman, Paul. "Duchenne and Facial Expression of Emotion: Paul Ekman." The Mechanism of Human Facial Expression.(2003) .
MLA-viite (8. p.)Ekman, Paul. "Duchenne and Facial Expression of Emotion: Paul Ekman." The Mechanism of Human Facial Expression.(2003), .
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.