GALDINO, A. L.; AYALA-RINCÓN, M. A Formalization of Newman’s and Yokouchi’s Lemmas in a Higher-Order Language. Journal of Formalized Reasoning, [S. l.], v. 1, n. 1, p. 39–50, 2008. DOI: 10.6092/issn.1972-5787/1347. Disponível em: https://jfr.unibo.it/article/view/1347. Acesso em: 8 feb. 2023.