SYSTEM, Journal. 0 - Prelim. Africa Development, [S. l.], v. 6, n. 4, 1981. DOI: 10.57054/ad.v6i4.3279. Disponível em: https://www.journals.codesria.org/index.php/ad/article/view/3279. Acesso em: 6 aug. 2025.