Rumanti, E. R. “Measurement Of The Stenosis Mitral by Using The Method Flow Convergence Or Proximal Isovelocity Area (PISA) And Planimetri”. ARKAVI [Arsip Kardiovaskular Indonesia], vol. 3, no. 2, July 2018, pp. 211-2013, https://journal.uhamka.ac.id/index.php/arkavi/article/view/5482.