Tiaprapong, K., W. Eungpinichpong, S. Wanpen, T. Kamolrat, and N. Manimmanakorn. “The Immediate Effects of the Self-Foot Massage Using Coconut Shell on Perceived Foot Fatigue, and Heart Rate Variability in Sedentary Healthy Subjects”. Archives of Allied Health Sciences, vol. 29, no. 2, Dec. 2017, pp. 180-94, https://he01.tci-thaijo.org/index.php/ams/article/view/107094.