Naeem, M.; Aziz, M.; Saeed, B.; Hashmi, S. D.; Ali, M.; Jalil, M. Using Pre-Operative Incentive Spirometer Reduces Chances of Basal Atelectasis in Patients Undergoing Upper Abdominal Surgeries - A Randomized Controlled Trial. Pak Armed Forces Med J 2025, 75 (SUPPL-2), S164-S168. https://doi.org/10.51253/pafmj.v75iSUPPL-2.11141.