Chaikipinyo S, Soontrapa S, Mahakkanukrauh C. Normative Reference Grading Program. SRIMEDJ [Internet]. 2013 Nov. 11 [cited 2024 May 3];4(3):218-27. Available from: https://li01.tci-thaijo.org/index.php/SRIMEDJ/article/view/13505