HERBST, P. Echocardiography: Is there unseen risk in cardiac ultrasound?. SA Heart Journal, [S. l.], v. 7, n. 2, p. 86–89, 2017. DOI: 10.24170/7-2-1950. Disponível em: https://www.journals.ac.za/SAHJ/article/view/1950. Acesso em: 8 oct. 2025.