VAN DER WALT, B. J. ? Onsuiwer mensbeskouing, kenteorie en wetenskapsleer in die Synopsis Purioris Theologiae (1625): ? Christelik-filosofiese verkenning. Tydskrif vir Christelike Wetenskap | Journal for Christian Scholarship, [S. l.], v. 47, n. 3 - 4, p. 49–86, 2011. Disponível em: https://pubs.ufs.ac.za/index.php/tcw/article/view/265. Acesso em: 5 oct. 2025.