AMTONG, C. The Study of English Language Development to Promote Tourism in Phetchabun Province: A Case Study of Tourist Assistant Officers in Muang District, Phetchabun Province. Research and Development Journal, Loei Rajabhat University, [S. l.], v. 18, n. 64, p. 73–83, 2023. Disponível em: https://so05.tci-thaijo.org/index.php/researchjournal-lru/article/view/254516. Acesso em: 16 sep. 2026.