SABLIK, Maciej. Differentiable solutions of functional equations in Banach spaces. Annales Mathematicae Silesianae, [S. l.], v. 7, p. 17–55, 1993. Disponível em: https://journals.us.edu.pl/index.php/AMSIL/article/view/14244. Acesso em: 5 dec. 2025.