LIEBENBERG-ENSLIN, H. PRESIDENT’S MESSAGE. Clean Air Journal, [S. l.], v. 18, n. 1, p. 2, 2010. DOI: 10.17159/caj/2010/18/1.7083. Disponível em: https://cleanairjournal.org.za/article/view/7083. Acesso em: 2 feb. 2023.