NKWOCHA, E.; OKEOMA, I. Street littering in Nigerian towns: towards framework for sustainable urban cleanliness. African Research Review, [S. l.], v. 3, n. 5, 2010. DOI: 10.4314/afrrev.v3i5.51149. Disponível em: https://www.ajol.info/index.php/afrrev/article/view/51149. Acesso em: 30 aug. 2026.