Akharawatthanakun, P. “An Overview of Research Studies on Southwestern Tai Languages and Language Variation and Change during the Four Decades (AD 1981–2021)”. Language and Linguistics, vol. 42, no. 1, June 2024, pp. 1-31, https://so04.tci-thaijo.org/index.php/joling/article/view/268738.