Ngamjarus, Chetta. “n4Studies: Sample Size Calculation for an Epidemiological Study on a Smart Device”. Siriraj Medical Journal 68, no. 3 (June 9, 2016): 160–170. Accessed March 29, 2024. https://he02.tci-thaijo.org/index.php/sirirajmedj/article/view/58342.