Chaiyachat, C., and A. Panthong. “Development of Mathematical Problem-Solving Skills using Polya’s Problem-Solving Process Combined with Bar Model Technique on Linear Equations with One Variable for Grade 7 Students in The Wachiraprakan School”. NSRU Journal of Research and Innovation, vol. 1, no. 2, Aug. 2026, pp. 58-72, https://so14.tci-thaijo.org/index.php/PATRU/article/view/2801.