MALEJKI, R. Stability of a generalization of the Fréchet functional equation. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 14, p. 69–79, 2015. Disponível em: https://studmath.uken.krakow.pl/article/view/13155. Acesso em: 31 oct. 2026.