Karwiky, G., C. Achmad, E. Martanto, and F. Sanjaya. “Correlation Of Left Ventricular Ejection Fraction And Spatial QRS-T Angle In Old Myocardial Infarct Patient”. Indonesian Journal of Cardiology, Vol. 42, no. 2, Sept. 2021, doi:10.30701/ijc.1092.