Naeem, Muhammad, Majid Aziz, Bilal Saeed, Syed Daood Hashmi, Muhammad Ali, and Meezan Jalil. “Using Pre-Operative Incentive Spirometer Reduces Chances of Basal Atelectasis in Patients Undergoing Upper Abdominal Surgeries - A Randomized Controlled Trial”. Pakistan Armed Forces Medical Journal 75, no. SUPPL-2 (March 25, 2025): S164-S168. Accessed June 14, 2025. https://www.pafmj.org/PAFMJ/article/view/11141.