Awan, Zahid Aslam, Muhammad Gallagher, E. Rowland, and AJ Camm. 2011. “Flutter Wave Polarity on Sruface ECG and Endocardial Activation in Typical Counter Clockwise Atrial Flutter”. Journal of Postgraduate Medical Institute 18 (4). https://jpmi.org.pk/index.php/jpmi/article/view/951.