van Zyl, Pieter G., Johan P. Beukes, Grizelda du Toit, Desmond Mabaso, Johan Hendriks, Ville Vakkari, Petri Tiitta, Jacobus J. Pienaar, Markku Kulmala, and Lauri Laakso. 2014. “Assessment of Atmospheric Trace Metals in the Western Bushveld Igneous Complex, South Africa”. South African Journal of Science 110 (3/4):1-11. https://doi.org/10.1590/sajs.2014/20130280.