Napitupulu, E., Wahyuni, F., Tobing, T., Ali, M., & Lubis, B. (2011). Correlation between hemoglobin level and left ventricular systolic functions and dimensions in children with chronic severe anemia. Paediatrica Indonesiana, 51(2), 79-83. https://doi.org/10.14238/pi51.2.2011.79-83