Kasenda, Richard, and Susy A Jael. “Effects of Laughter on Quality and Hours of Sleep and Blood Pressure Among Elderly in Indonesia”. Journal of International Scholars Conference - ALLIED HEALTH 1, no. 5 (January 1, 2016): 62-70. Accessed May 8, 2021. https://jurnal.unai.edu/index.php/jiscah/article/view/385.