กีรติวิบูลย์ ว. Comparisons of Opinions between Students Unwithdrawn and Withdrawn Calculus 1 of Thaksin University. KKU Sci. J. [internet]. 2016 Mar. 30 [cited 2026 Aug. 27];44(1):222-36. available from: https://ph01.tci-thaijo.org/index.php/KKUSciJ/article/view/249492