MACHURA, Piotr. Moral norms, moral ideals and supererogation. Folia Philosophica, [S. l.], v. 29, p. 277–305, 2011. DOI: 10.31261/fp.21392. Disponível em: https://journals.us.edu.pl/index.php/FOLIA/article/view/21392. Acesso em: 5 dec. 2025.