O. Ndoro, T., and L. K. Witika. “A Review of the Flotation of Copper Minerals”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 34, no. 2, July 2017, pp. 145-6, https://www.gssrr.org/index.php/JournalOfBasicAndApplied/article/view/7590.