Suleman, A., Z. Iqbal, R. Ullah, S. Ullah, H. N. Khan, and S. Naz. “Frequency of Depression in Patients With Bronchial Asthma”. Pakistan Journal of Chest Medicine, vol. 24, no. 3, Sept. 2018, pp. 158-62, https://pjcm.net/index.php/pjcm/article/view/550.