Shabbir, Faizania, et al. “Frequency of Various Risk Factors and Their Correlation With Outcome in Complete Heart Block Patients Coming to a Tertiary Care Hospital”. Pakistan Journal of Physiology, vol. 16, no. 2, June 2020, pp. 26-29, https://pjp.pps.org.pk/index.php/PJP/article/view/1176.