DOUBELL, A. Hellmuth Friederich Heyderhoff Weich: 19/01/1937 - 14/4/2007. SA Heart Journal, [S. l.], v. 4, n. 3, p. 48–51, 2017. DOI: 10.24170/4-3-2091. Disponível em: https://www.journals.ac.za/SAHJ/article/view/2091. Acesso em: 8 oct. 2025.