GUO, H.; SUN, Y. Research on Materials Classification Model Building and Procurement Strategy of Coal Enterprises. Journal of Mines, Metals and Fuels, [S. l.], v. 65, n. 12, p. 691–695, 2017. DOI: 10.18311/jmmf/2017/26938. Disponível em: https://www.informaticsjournals.com/index.php/jmmf/article/view/26938. Acesso em: 5 may. 2024.