CHLASTAWA, D. The modal status of mathematical statements (in Polish). Diametros, [S. l.], n. 30, p. 2–12, 2011. DOI: 10.13153/diam.30.2011.452. Disponível em: https://diametros.uj.edu.pl/diametros/article/view/452. Acesso em: 27 jan. 2023.