Balthip, K. ., B. . Suwanphahu, and S. . Laimek. “Development of a Purpose in Life Scale for Thai Adolescents: A Mixed-Method Study”. Kasetsart Journal of Social Sciences, vol. 43, no. 3, July 2022, pp. 561–568, https://so04.tci-thaijo.org/index.php/kjss/article/view/260293.