Navaruttanaporn S. Developing the Instructional Self-learning Media of English Speaking Skills for Hotel Front Office Staff in Muang District, Loei Province. LRUJ [internet]. 2021 Jan. 5 [cited 2026 Sep. 29];16(55):105-16. available from: https://so05.tci-thaijo.org/index.php/researchjournal-lru/article/view/243744