Wannajak, K., S. Leethongdissakul, and P. Hirunwatthanakul. “Health service development model to reduce waiting time in out-patient department at Namon Hospital, Kalasin Province”. UBRU Journal for Public Health Research, vol. 12, no. 3, Dec. 2023, pp. 82-91, https://he02.tci-thaijo.org/index.php/ubruphjou/article/view/264795.