KRZYWKOWSKI, M. P. On the hat problem, its variations, and their applications. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 9, p. 55–68, 2010. Disponível em: https://studmath.uken.krakow.pl/article/view/13246. Acesso em: 31 oct. 2026.