Thurathong, T., D. Chancharoen, K. Tanchaisak, and C. Cruthaka. “The Development of a Training Program to Enhance the Essential Competencies of Salespersons in the Beauty Surgery Business”. Ph.D. In Social Sciences Journal, vol. 12, no. 3, Dec. 2022, pp. 745-58, https://so05.tci-thaijo.org/index.php/phdssj/article/view/247998.