Upa, C., and K. Pornprapa. “FACTORS AFFECTING DECISION MAKING OF SELF-EMPLOYED TO BE INSURED UNDER SECTION 40 OF THE SOCIAL SECURITY ACT CASE STUDY: RATCHABURI PROVINCE”. Journal of Graduate School of Commerce-Burapha Review, vol. 17, no. 1, June 2022, pp. 77-94, https://so02.tci-thaijo.org/index.php/GSC/article/view/250075.