Phumphothong, P., and P. Nugbanleng. “Factors Affecting the Purchasing Decision Making of Fixed Price Product from Department Stores at Muang District, Phitsanulok”. Economics and Business Administration Journal Thaksin University, vol. 13, no. 1, June 2021, pp. 113-30, https://so01.tci-thaijo.org/index.php/ecbatsu/article/view/240323.