P.P. Diale and  S.S.L. Mkhize and  E. Muzenda and  J. Zimba,  The Sequestration of Heavy Metals Contaminating the Wonderfonteinspruit Catchment Area using Natural Zeolite.   journal   = {International Journal of Materials and Metallurgical Engineering}, [online]. World Academy of Science, Engineering and Technology.
    February 2011, vol. 50(2). 196 - 202
    [viewed 26 April 2024]. Available from: https://publications.waset.org/pdf/595.