Toomrachaya, Jarkapong. 2020. “The Operation of sub–district Municipalities in Donchan District, Donchan District Kalasin Province”. Journal of Research and Development Institute Rajabhat Maha Sarakham University 7 (1):1-12. https://so03.tci-thaijo.org/index.php/rdirmu/article/view/245033.