Brown S. L. & Schwartz G. E. (1980) Relationships between facial electromyography and subjective experience during affective imagery. Biological Psychology 11:49–62.
Ekman P., Davidson R. J. & Friesen W. V. (1990) The Duchenne smile: Emotional expression and brain physiology: II. Journal of Personality and Social Psychology 58:342–53.
Ekman P., Friesen W. V. & Ancoli S. (1980) Facial signs of emotional experience. Journal of Personality and Social Psychology 39:1125–34.
Friedman S. & Miller-Herringer T. (1991) Nonverbal display of emotion in public and in private: Self-monitoring, personality, and expressive cues. Journal of Personality and Social Psychology 61:766–75.
Gehricke J. G. & Fridlund A. J. (2002) Smiling, frowning, and autonomic activity in mildly depressed and nondepressed men in response to emotional imagery of social contexts. Perceptual Motor Skills 94:141–51.
Hall J. A. & Horgan T. G. (2003) Happy affect and smiling: Is their relation moderated by interpersonal power? Emotion 3:303–309.
Hecht M. A. & LaFrance M. (1998) License or obligation to smile: The effect of power and sex on amount and type of smiling. Personality and Social Psychology Bulletin 24:1332–42.
Hess U., Banse R. & Kappas A. (1995) The intensity of facial expression is determined by underlying affective state and social situation. Journal of Personality and Social Psychology 69:280–88.
Jakobs E., Manstead A. S. R. & Fischer A. H. (2001) Social context effects on facial activity in a negative emotional setting. Emotion 1:51–69.
Kraut R. E. & Johnston R. E. (1979) Social and emotional messages of smiling: An ethological approach. Journal of Personality and Social Psychology 37:1539–53.
LaFrance M. & Hecht M. A. (2000) Gender and smiling: A meta-analysis of sex differences in smiling. In: Gender and emotion: Social Psychological Perspectives, ed. Fischer A. H., pp. 118–42. Cambridge University Press.
Larsen J. T., Norris C. J. & Cacioppo J. T. (2003) Effects of positive and negative affect on electromyographic activity over zygomaticus major and corrugator supercilii. Psychophysiology 40:776–85.
Polk D. E., Cohen S., Doyle W. J., Skoner D. P. & Kirschbaum C. (2005) State and trait affect as predictors of salivary cortisol in healthy adults. Psychoneuroendocrinology 30:261–72.
Ruiz-Belda M. A., Fernández-Dols J. M. & Carrera P. (2003) Spontaneous facial expression of happy bowlers and soccer fans. Cognition and Emotion 17:315–26.
Schwartz G. E., Brown S. L. & Ahern G. L. (1980) Facial muscle patterning and subjective experience during affective imagery: Sex differences. Psychophysiology 17:75–82.
Watson D., Clark L. A. & Tellegen A. (1988) Development and validation of a brief measure of positive and negative affect. Journal of Personality and Social Psychology 54:1063–70.