Sofia Shoukat, Maheen Saad, Muhammad Razaq, Nadia Qazi, Jahangir Zaib, and Tahira Jehangir. 2022. “Role of Pneumococcal and Influenza Vaccine in Prevention and Vitamin E With Beta Carotene in Treatment of Pneumonia in Patients With COPD”. Pakistan Journal of Chest Medicine 28 (1):13-19. https://www.pjcm.net/index.php/pjcm/article/view/849.