Ponyiam, Waraporn, and Charan Lengvithaya. “The Development of Tourism and Tour Guides Laws Under the Tourism Business and Guide Act B.E. 2551”. Ph.D. in Social Sciences Journal 11, no. 2 (August 30, 2021): 283–294. Accessed April 26, 2024. https://so05.tci-thaijo.org/index.php/phdssj/article/view/193418.