Siregar, G. A., and Z. Z. Tala. “Association Between CTLA-4 Gene Polymorphism and Risk of Hepatocellular Carcinoma in Chronic Hepatitis B Patients”. Open Access Macedonian Journal of Medical Sciences, vol. 10, no. B, Apr. 2022, pp. 896-9, doi:10.3889/oamjms.2022.9095.