Vilela, Eduardo, Susana Torres, Helena Gonçalves, João Primo, Madalena Teixeira, and Pedro Braga. “Complete Atrioventricular Block During Exercise: New Insights from an Old Test”. Monaldi Archives for Chest Disease 89, no. 1 (January 29, 2019). Accessed June 27, 2019. https://monaldi-archives.org/index.php/macd/article/view/1002.