Sitorus, Ridho Firmansyah. “Correlation Between Helicobacter Pylori VacA Antibody Serum and Gastric Premalignant Lesions in Helicobacter Pylori Patients”. Journal of Society Medicine, vol. 2, no. 11, Nov. 2023, pp. 348-56, doi:10.47353/jsocmed.v2i11.92.