Nawsuwan, K., and N. Singweratham. “Factor Analysis on New Normal Medical Services during COVID-19’s Outbreak in Out Patient Department of Health Care Provider under Ministry of Public Health”. Princess of Naradhiwas University Journal, vol. 15, no. 1, Jan. 2023, pp. 173-86, https://li01.tci-thaijo.org/index.php/pnujr/article/view/256261.