กีรติวิบูลย์ วรางคณา. 2015. “A Study of The Correlation Among The Personal Factors Affecting on Learning Achievement of Calculus 1 for Thaksin University’s Students”. Parichart Journal 28 (2):88-107. https://so05.tci-thaijo.org/index.php/parichartjournal/article/view/43188.