RIEDEL, T.; WALLACE, K. On a Pexider type equation on Δ⁺. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 1, p. 129–137, 2001. Disponível em: https://studmath.uken.krakow.pl/article/view/13523. Acesso em: 30 oct. 2026.