STEYN, M.; KORNELIUS, G. An economic assessment of SO2 reduction from industrial sources on the highveld of South Africa. Clean Air Journal, [S. l.], v. 28, n. 1, 2018. DOI: 10.17159/2410-972X/2018/v28n1a9. Disponível em: https://cleanairjournal.org.za/article/view/6960. Acesso em: 22 oct. 2021.