ชนะสิทธิ์ ก., and พสุนนท์ ป. “SAMPLING AND INTEGRATION BASED ON MIXED METHODS RESEARCH”. Journal of Humanities and Social Sciences Thonburi University, vol. 12, no. 29, Sept. 2018, pp. 147-58, https://so03.tci-thaijo.org/index.php/trujournal/article/view/145182.