M. . Fahim, M. . Sohail, M. Sajjad Khan, F. U. . Khan, S. . Ur Rashid, and S. . Akhter, “Frequency of Bleeding Duodenal Ulcer in Patients Presenting with Upper Gastrointestinal Bleeding: Frequency of Duodenal Ulcer in patients with Gastrointestinal Bleeding”, PJHS, vol. 3, no. 06, pp. 88–92, Nov. 2022.