OKREGLICKI, A. ECG Quiz no. 21. SA Heart Journal, [S. l.], v. 7, n. 4, p. 280, 2017. DOI: 10.24170/7-4-1940. Disponível em: https://www.journals.ac.za/SAHJ/article/view/1940. Acesso em: 8 oct. 2025.