Sawangsri, B. “STUDY OF MATHEMATICS ACHIEVEMENT BY USING LEARNING ACTIVITIES THAT PROMOTE PROBLEM-SOLVING SKILLS AND MATHEMATICAL CONNECTION SKILLS”. Journal of Liberal Art of Rajamangala University of Technology Suvarnabhumi, vol. 4, no. 1, Apr. 2022, pp. 56-68, https://so03.tci-thaijo.org/index.php/art/article/view/252488.