Tullapong, S., P. Juntasopeepun, and R. Jintanawat. “Factors Predicting COVID-19 Vaccination Intention of Unvaccinated Older Adults in Phetchabun Province”. Nursing Journal CMU, vol. 51, no. 4, Dec. 2024, pp. 119-32, https://he02.tci-thaijo.org/index.php/cmunursing/article/view/265496.