KOSTRA, Juraj. Open problems on the relation between additive and multiplicative structure. Annales Mathematicae Silesianae, [S. l.], v. 16, p. 21–25, 2003. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14105. Acesso em: 7 may. 2025.