Hassaan, M.; Ajmal, M.; Butt, N. I.; Aftab, S.; Ashfaq, F.; Tareen, M. Q. FREQUENCY OF PULMONARY HYPERTENSION USING ECHOCARDIOGRAPHY IN PATIENTS OF IDIOPATHIC PULMONARY FIBROSIS AT A TERTIARY CARE HOSPITAL. J Postgrad Med Inst 2022, 36, 121-4.