Rifkin, Riaan F., Francesco d’Errico, Laure Dayet-Boulliot, and Beverley Summers. “Assessing the Photoprotective Effects of Red Ochre on Human Skin by in Vitro Laboratory Experiments”. South African Journal of Science 111, no. 3/4 (March 27, 2015): 1–8. Accessed March 29, 2024. https://sajs.co.za/article/view/3568.