Popukdee, S., Yarana, C., Pothasin, V., & Yanatham, B. (2026). Developing Thai tone writing skills using Tone writing practice With tone rules (Tone Rules) For International Primary School Grade 6 students Unity Concord International. Phimoldhamma Research Institute Journal, 13(2). retrieved from https://so06.tci-thaijo.org/index.php/prij/article/view/294588