Khan, Bilal Irshad, et al. “Frequency of Helicobacter Pylori (H. Pylori) in Patients Operated for Duodenal Ulcer Perforation”. Biological and Clinical Sciences Research Journal, vol. 6, no. 8, Aug. 2025, pp. 121-4, doi:10.54112/bcsrj.v6i8.2186.