VAN NIEKERK, E. J. (Johan). Gratitude in teacher leadership. Tydskrif vir Christelike Wetenskap | Journal for Christian Scholarship, [S. l.], v. 52, n. 3, p. 21–41, 2016. Disponível em: https://pubs.ufs.ac.za/index.php/tcw/article/view/402. Acesso em: 5 nov. 2025.