Germishuys, Ryno, and Roger Diamond. “Nitrogen Isotopes of Eichhornia Crassipes (water Hyacinth) Confirm Sewage As Leading Source of Pollution in Hartbeespoort Reservoir, South Africa”. South African Journal of Science 118, no. 7/8 (July 28, 2022). Accessed April 20, 2024. https://sajs.co.za/article/view/11098.