McGuire, Adam P, Thane M Erickson, Christina M Quach, and Brittany Willey. “Gratitude for Better or Worse: Differential Predictors and Affective Outcomes of State Gratitude in Positive and Negative Contexts”. Journal of Positive Psychology and Wellbeing00 (October 15, 2018): 1-13. Accessed June 18, 2019. http://journalppw.com/index.php/JPPW/article/view/91.