OFFIONG, R.; ATU, J.; NJAR, G.; AMUYOU, U. Problems and prospects of poor drainage systems and urban sustainabilty in Calabar, Nigeria. Global Journal of Social Sciences, [S. l.], v. 7, n. 2, 2009. DOI: 10.4314/gjss.v7i2.48852. Disponível em: https://www.ajol.info/index.php/gjss/article/view/48852. Acesso em: 6 oct. 2026.