Yasin, Mohammad, Wisal Ahmad, Muhammad Abbas, Saadia Ashraf, and Faheem Jan. 2024. “Correlation Between FEV1 and Polycythemia in Chronic Obstructive Pulmonary Disease”. Pakistan Journal of Chest Medicine 30 (3):298-304. https://pjcm.net/index.php/pjcm/article/view/931.