, . . English summaries. Butlletí de la Societat Catalana de Matemàtiques, [S. l.], v. 22, n. 2, p. 229–231, 2008. Disponível em: https://revistes.iec.cat/index.php/BSCM/article/view/33990.001. Acesso em: 6 may. 2024.