ALT, Heinrich. The Problem of Universals. Tydskrif vir Christelike Wetenskap | Journal for Christian Scholarship, [S. l.], n. 1, p. 1–15, 2006. Disponível em: https://pubs.ufs.ac.za/index.php/tcw/article/view/88. Acesso em: 27 oct. 2025.