WALKER, N. The spatial distribution of trace elements in Pretoria. Clean Air Journal, [S. l.], v. 6, n. 4, 1983. DOI: 10.17159/caj/1983/6/4.7265. Disponível em: https://cleanairjournal.org.za/article/view/7265. Acesso em: 3 jul. 2024.