Shaheen, S. . ., Humayun , A. ., Zaib, J. . . ., Bukhari , S. M. S. A. ., Jadoon, M. . and Sammar, K. . . (2023) “The correlation between Cytokines imbalance and Vitamin D level in Patients with early Chronic Obstructive Pulmonary Disease (COPD) and the role of Vitamin D in Pulmonary Disease”, Pakistan Journal of Chest Medicine, 29(2), pp. 192–198. doi: 10.1996/pjcm.v29i2.838.