OKREGLICKI, A. Answer to ECG Quiz no. 7. SA Heart Journal, [S. l.], v. 4, n. 2, p. 48–49, 2017. DOI: 10.24170/4-2-2101. Disponível em: https://www.journals.ac.za/SAHJ/article/view/2101. Acesso em: 8 oct. 2025.