PALFREY, Thomas C. Density theorems for reciprocity equivalences. Annales Mathematicae Silesianae, [S. l.], v. 12, p. 161–172, 1998. Disponível em: https://journals.us.edu.pl/index.php/AMSIL/article/view/14177. Acesso em: 18 apr. 2025.