Selenge, Baasansuren, Sarnai Tsagaankhuu, and Damdindorj Boldbaatar. “Principles of Research Methodology A Guide for Clinical Investigators”. Central Asian Journal of Medical Sciences 9, no. 1 (March 30, 2023): 62–63. Accessed June 30, 2024. https://mongoliajol.info/index.php/CAJMS/article/view/3112.