Jamal, Syed Zahid, et al. “LOCALIZATION OF ACCESSORY PATHWAYS IN WOLFF PARKINSON WHITE SYNDROME USING R S RATIOS ON SURFACE ECGs”. Journal of Ayub Medical College Abbottabad, vol. 31, no. 2, Mar. 2019, pp. 146-50, https://www.jamc.ayubmed.edu.pk/index.php/jamc/article/view/4528.