NGUYEN VAN DUNG. \(ls\)-Ponomarev-systems and 1-sequence-covering mappings. Scientia, [S. l.], v. 19, p. 25–36, 2025. DOI: 10.71712/. Disponível em: https://revistas.usm.cl/scientia/article/view/136. Acesso em: 13 jun. 2026.