Tangjittrong, Kittisak. “Changes in serum 25-hydroxyvitamin D and intact parathyroid hormone level following treatment with ergocalciferol among patients with chronic kidney disease”. Journal of the Nephrology Society of Thailand 28, no. 1 (August 25, 2022): 62–67. accessed December 7, 2025. https://he01.tci-thaijo.org/index.php/JNST/article/view/258860.