Thepnarong, Thanakorn, and Kittitas Wancham. “Development of Parallelism Test on Linear Equations with One Variable”. An Online Journal of Education 21, no. 2 (August 26, 2026): 1–20. accessed August 27, 2026. https://so01.tci-thaijo.org/index.php/OJED/article/view/288040.