Shabbir, Muhammad, et al. “VALIDATION OF DIAGNOSTIC ACCURACY OF LEADS AVR AND V1 IN ATRIOVENTRICULAR NODAL REENTRANT TACHYCARDIA (AVNRT)”. Pakistan Armed Forces Medical Journal, vol. 65, no. (SUPPL), Mar. 2015, pp. S86-9, https://pafmj.org/PAFMJ/article/view/4419.