ZHANG, K. .; JI, C. .; REN, H. . Improving Economic Benefits through Coal Products Optimization in a Given Group. International Journal of Economics, Business and Management Studies, [S. l.], v. 4, n. 1, p. 57–64, 2017. DOI: 10.20448/802.41.57.64. Disponível em: https://onlinesciencepublishing.com/index.php/ijebms/article/view/214. Acesso em: 26 apr. 2024.