“The Effectiveness Of Writing The Letter Of Gratitude Technique In Reducing The Stress Level Of Islamic Boarding School Student”. Psikis : Jurnal Psikologi Islami 7, no. 1 (June 30, 2021): 79–85. Accessed April 1, 2025. https://jurnal.radenfatah.ac.id/index.php/psikis/article/view/4612.