Almani, Suhail Ahmed, et al. “Response of H. Pylori Eradication Treatment in Patients With Normal and Below Normal Serum Vitamin D Levels”. Journal of Liaquat University of Medical & Health Sciences, vol. 19, no. 04, Dec. 2020, pp. 242-6, http://121.52.154.205/index.php/jlumhs/article/view/485.