Treewai, C., P. Meejaisue, M. Piriyakul, and T. Boonkwan. “The Structural Equation Model of Factors Effecting Customer Behavior of Spa Service in Bangkok Metropolis”. Ph.D. In Social Sciences Journal, Vol. 10, no. 1, Apr. 2020, pp. 255-67, https://so05.tci-thaijo.org/index.php/phdssj/article/view/139971.