H. B. . Khan, M. S. . Khattak, M. . Durrani, A. . Hussain, S. Y. . Khan, and A. U. . Rehman, “Exploring the Role of Vitamin D3 in Addressing Lung Dysfunction and Small Airways Degeneration in Chronic Obstructive Pulmonary Disease ”, Pak J Chest Med, vol. 27, no. 4, pp. 310–315, Dec. 2021.