Weerapol, P., and A. Charanyananda. “Thai Guitarist’s Self-Directed Learning: A Case Study of Thammarat Duangsiri”. Journal of Fine and Applied Arts Khon Kaen University, vol. 12, no. 1, June 2020, pp. 180-06, https://so02.tci-thaijo.org/index.php/fakku/article/view/197412.