Thetlek, A. . . “The Development of Supplementary Reading Materials on Travel to Samphran to Enhance The Ability of Reading For Main Idea For Prathomsuksa 6 Students”. Journal of MCU Social Science Review, vol. 6, no. 1, Aug. 2020, pp. 91-102, https://so03.tci-thaijo.org/index.php/jssr/article/view/245576.