Christanto, Stefanus Arista, Dea Brenda, Clara Assisiansi, Maria Jessica Pangestu, Ignatia Sarita, and Vania Sulistiani. “Gratitude Letter: An Effort to Increase Subjective Well-Being in College”. ANIMA Indonesian Psychological Journal 32, no. 3 (April 25, 2017): 158-168. Accessed July 22, 2024. https://journal.ubaya.ac.id/index.php/jpa/article/view/Gratitude%20Letter.