Al-Alousi, Maha, et al. “The Prevelance of Hepatitis B Surface Antigen (HBsAg) Among Blood Donors in Some Hospitals of Thamar, Yemen”. Thamar University Journal of Natural & Applied Sciences, vol. 5, no. 1, Jan. 2023, pp. 1-9, doi:10.59167/tujnas.v5i5.1300.