COSTS OF TRACTOR OWNERSHIP UNDER DIFFERENT MANAGEMENT SYSTEMS IN NIGERIA. Nigerian Journal of Technology, [S. l.], v. 19, n. 1, p. 15–28, 2003. DOI: 10.4314/njt.191.439. Disponível em: https://nijotech.com/index.php/nijotech/article/view/439. Acesso em: 16 apr. 2026.