A Proof of the Four-Color Problem based on a New Law of Logic the Law of the Middle Term. London Journal of Research In Science: Natural and Formal, [S. l.], v. 23, n. 4, p. 107–112, 2023. Disponível em: https://journalspress.uk/index.php/LJRS/article/view/391. Acesso em: 2 feb. 2026.