WESSELS, D. C. J. Die Identifisering van die Elementêre Grondbegrippe in die Wiskunde. Tydskrif vir Christelike Wetenskap | Journal for Christian Scholarship, [S. l.], v. 42, n. 4, p. 171–205, 2006. Disponível em: https://pubs.ufs.ac.za/index.php/tcw/article/view/87. Acesso em: 11 oct. 2025.