McCullough, M. E., Tsang, J. & Emmons, R. A. (2004). Gratitude in intermediate affective terrain: Links of grateful moods to individual differences and daily emotional experience. Journal of Personality and Social Psychology, 86,295-309. [1]Arkivigite je 2019-11-04 per la retarkivo Wayback Machine
Linley, P. A., Joseph, S., Harrington, S., & Wood, A. M. (2006). Positive psychology: Past, present, and (possible) future. Arkivita la 5an de marto 2016 en Wayback The Journal of Positive Psychology, 1, 3-16. Alirita la 4an de novembro 2019.
McCullough, M. E., Tsang, J. & Emmons, R. A. (2004). Gratitude in intermediate affective terrain: Links of grateful moods to individual differences and daily emotional experience. Journal of Personality and Social Psychology, 86,295-309. [1]Arkivigite je 2019-11-04 per la retarkivo Wayback Machine