CICHOŃ, D. À la recherche de la preuve perdue: a simple proof of the Ficken theorem. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 13, p. 133–137, 2014. Disponível em: https://studmath.uken.krakow.pl/article/view/13198. Acesso em: 29 oct. 2026.