BOARD, E. Thermal coal in 2021. Journal of Mines, Metals and Fuels, [S. l.], v. 69, n. 1, p. 4–4, 2021. DOI: 10.18311/jmmf/2021/27315. Disponível em: https://informaticsjournals.com/index.php/jmmf/article/view/27315. Acesso em: 7 jun. 2023.