A Universal Relation Approach For Natural Query In Logic Database System. Jurnal Teknologi, [S. l.], v. 20, n. 1, p. 46–64, 1992. DOI: 10.11113/jt.v20.1065. Disponível em: https://journals.utm.my/jurnalteknologi/article/view/1065.. Acesso em: 23 jul. 2024.