NIKI, S. Empirical Negation, Co-Negation and the Contraposition Rule II: Proof-Theoretical Investigations . Bulletin of the Section of Logic, [S. l.], v. 49, n. 4, p. 359–375, 2020. DOI: 10.18778/0138-0680.2020.13. Disponível em: https://czasopisma.uni.lodz.pl/bulletin/article/view/8164. Acesso em: 4 may. 2024.