Punsuwun, S., K. Mahakittikun, P. Uthchachon, and U. Kanathum. “Effects of Positive Self-talk Training Program on Self-esteem and Psychological Well-being Among Pregnant Adolescents”. Journal of Research in Nursing-Midwifery and Health Sciences, vol. 37, no. 2, June 2017, pp. 77-89, https://he02.tci-thaijo.org/index.php/nur-psu/article/view/91405.