Theerawongnukul, Hongfah, Archanya Ratana-Ubol, and Ying Keeratiburana. 2014. “The Development of A Program to Enhance Self-Esteem and Social Skills of Non-Formal Education Students”. Journal of Education Studies, Chulalongkorn University 42 (December). Bangkok, Thailand:92-109. https://so02.tci-thaijo.org/index.php/EDUCU/article/view/26462.