Wahyuni, F., M. Ali, B. Lubis, N. Lubuis, and T. Tobing. “Hemoglobin Level and Cardiothoracic Ratio in Children With Chronic Severe Anemia”. Paediatrica Indonesiana, Vol. 51, no. 5, Oct. 2011, pp. 262-5, doi:10.14238/pi51.5.2011.262-5.