Ahmad, Waqas, Saood Khan, and Muhammad Shahzad. “Small Airways Dysfunction and Neutrophilic Inflammation in Acute COPD Exacerbations: A Cross-Sectional Study”. Pakistan Journal of Chest Medicine 31, no. 4 (December 2, 2025): 335–345. Accessed April 22, 2026. http://www.pjcm.net/index.php/pjcm/article/view/1076.