Amrollah Sharifi, et al. “Vitamin D Decreases CD40L Gene Expression in Ulcerative Colitis Patients: A Randomized, Double-Blinded, Placebo-Controlled Trial”. Turkish Journal of Gastroenterology, vol. 31, no. 2, Mar. 2020, pp. 99-104, https://tjg.avesjournals.com/index.php/tjg/article/view/3850.