FRENCH, Rohan; HUMBERSTONE, Lloyd. An Observation Concerning Porte’s Rule in Modal Logic. Bulletin of the Section of Logic, Poland, v. 44, n. 1/2, p. 25–31, 2015. DOI: 10.18778/0138-0680.44.1.2.04. Disponível em: https://www.czasopisma.uni.lodz.pl/bulletin/article/view/16224. Acesso em: 9 aug. 2026.