KOMINEK, Zygfryd. On a problem of Wu Wei Chao. Annales Mathematicae Silesianae, [S. l.], v. 16, p. 17–20, 2003. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14104. Acesso em: 7 may. 2025.