Ekman, P., & Friesen, W. V. (1975). Unmasking the face : a guide to recognizing emotions from facial clues / (by) Paul Ekman and Wallace V. Friesen: A guide to recognizing emotions from facial clues. Prentice-Hall.
Chicago Style (17th ed.) CitationEkman, Paul, and Wallace V. Friesen. Unmasking the Face : A Guide to Recognizing Emotions from Facial Clues / (by) Paul Ekman and Wallace V. Friesen: A Guide to Recognizing Emotions from Facial Clues. Englewood Cliffs ; London (etc.): Prentice-Hall, 1975.
MLA (9th ed.) CitationEkman, Paul, and Wallace V. Friesen. Unmasking the Face : A Guide to Recognizing Emotions from Facial Clues / (by) Paul Ekman and Wallace V. Friesen: A Guide to Recognizing Emotions from Facial Clues. Prentice-Hall, 1975.
Warning: These citations may not always be 100% accurate.