Ekman, P. (1970). Universal facial expressions of emotions. California Mental Health Research Digest. 8(4), 151-158.
Frankl, V. (2006). Man's Search for Meaning. MS: Beacon Press.
Gruber, J., Mauss, I., & Tamir, M. (2011). A dark side of happiness? how, when, and why happiness is not always good, Perspectives on Psychological Science. 6(3), 222-233.
Kavaklı, M. (2019). Why do we have emotions? the social functions of emotions. Research on Education and Psychology. 3(1), 11-20.
Keltner, D., & Haidt, J. (1999). Social functions of emotions at four levels of analysis. Cognition & Emotion. 13(5), 505-521.
Verduyn, P., Mechelen, I., Kross, E., Chezzi, C., & Bever, F. (2012). The relationship between self-distancing and the duration of negative and positive emotional experiences in daily life. Emotion. 12(6), 1248-1263.
Watson, D., & Clark, A. (1984). Negative affectivity: The disposition to experience aversive emotional states. Psychological Bulletin. 96(3), 465–490.