TUTAJ, E. Likeℕ’s – a point of view on natural numbers. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 16, p. 95–115, 2018. Disponível em: https://studmath.uken.krakow.pl/article/view/12975. Acesso em: 21 jul. 2026.