Wangwon, C., and S. Pimthong. “Effectiveness of Positive Psychological Capital Program on Work Engagement of Employees of Non-Governmental Organizations (NGOs) on Gender Diversity”. Journal of Behavioral Science for Development, vol. 15, no. 1, Jan. 2023, pp. 108-24, https://so02.tci-thaijo.org/index.php/JBSD/article/view/259180.