HAMEED, A.; KHAN, W. A.; KAZMI, K. R.; BHATI, M. A.; SHAHZAD, K. Reduction of Sulfur and Ash of Salt Range Coal by Froth Flotation Technique. Journal of the Pakistan Institute of Chemical Engineers, [S. l.], v. 43, n. 2, p. 67–74, 2015. Disponível em: http://piche.org.pk/journal/index.php/jpiche/article/view/208. Acesso em: 23 apr. 2024.