Iftikhar Ali Kakar, Abdul Baqi, Nasir Azim, Hafsa Rafiq, Iqra Lodhi, Khalid Shahab (2023) “Pulmonary Arterial Hypertension in COPD and its Correlation with Disease Severity”, Pakistan Journal of Medical & Health Sciences, 16(12), p. 391. doi: 10.53350/pjmhs20221612391.