Singh, A. K., P. K. Mishra, R. B. Singh, M. kumar, and D. Singh. “Prediction of Morbidity and Mortality in Middle and Old Aged Surgical Patients-Comparison of Standard Scoring System and Addition of Echocardiography With Hemodynamic Indices”. International Journal of Research in Medical Sciences, vol. 3, no. 10, Jan. 2017, pp. 2543-8, doi:10.18203/2320-6012.ijrms20150787.