VAN DYK, D; LLEWELLYN, R L; GORDON, P C; BRINK, J G. Sylvia Annigje Magdalena Heijke (1955 - 2022). South African Medical Journal, South Africa, v. 113, n. 5, p. 4, 2023. Disponível em: https://samajournals.co.za/index.php/samj/article/view/898. Acesso em: 12 oct. 2025.