Watkins, P. C., Scheer, J., Ovnicek, M., & Kolts, R. (2006). The debt of gratitude: Dissociating gratitude and indebtedness. Cognition and Emotion, 20, 217-241, DOI: 10.1080/02699930500172291.
Park, Yoobin; Impett, Emily A.; MacDonald, Geoff; Lemay Jr., Edward P. (2019, Jan 31). Saying "thank you": Partners' expressions of gratitude protect relationship satisfaction and commitment from the harmful effects of attachment insecurity. Journal of Personality and Social Psychology. http://doi.org/10.1037/pspi0000178
Wood, A. M., Joseph, S., & Maltby, J. (2008). PersonalPages.Manchester.ac.ukArchiviato il 28 settembre 2011 in Internet Archive., Gratitude uniquely predicts satisfaction with life: Incremental validity above the domains and facets of the Five Factor Model. Personality and Individual Differences, 45, 49-54.
Wood, A. M., Joseph, S., & Maltby, J. (2008). PersonalPages.Manchester.ac.ukArchiviato il 28 settembre 2011 in Internet Archive., Gratitude uniquely predicts satisfaction with life: Incremental validity above the domains and facets of the Five Factor Model. Personality and Individual Differences, 45, 49-54.