NOWAK, Andrzej. A note on the Fréchet theorem. Annales Mathematicae Silesianae, [S. l.], v. 9, p. 43–45, 1995. Disponível em: https://journals.us.edu.pl/index.php/AMSIL/article/view/14204. Acesso em: 16 dec. 2025.