HALLIDAY, E.C. Air Pollution - Past, Present and Future. Clean Air Journal, [S. l.], v. 4, n. 1, p. 3–7, 1978. DOI: 10.17159/caj/1978/4/1.7384. Disponível em: https://cleanairjournal.org.za/article/view/7384. Acesso em: 17 may. 2024.