R. S. Kiani, R. Munawar, S. A. Bukhari, M. A. Quddus, and R. Tahir, “Assessment of Gastroesophageal Reflux Frequency and Its Clinical Impact in Severe Chronic Obstructive Pulmonary Disease”, Pak J Chest Med, vol. 30, no. 1, pp. 51–58, Mar. 2024.