MOSZNER, Z. On the stability of the squares of some functional equations. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 14, p. 81–104, 2015. Disponível em: https://studmath.uken.krakow.pl/article/view/13156. Acesso em: 30 oct. 2026.