Akbar, H.; Ullah, M.; Akhtar, K.; Sultan, M.; Sadiq, N. COMPARATIVE STUDY TO EVALUATE THE EFFICACY OF TRANSTHORACIC ECHOCARDIOGRAPHY VERSUS CARDIAC CATHETERIZATION FOR PRE OPERATIVE ASSESSMENT OF TETRALOGY OF FALLOT. Pak Armed Forces Med J 2014, 1 (1), S4-8.