van der Westhuizen, Derik, Gerhard Lachmann, and Henning Krieg. 2014. “The Possibility of Membrane-Based Solvent-Extraction (MBSX) As a Separation Method for Zr and Hf in Aqueous Solutions”. Suid-Afrikaans Tydskrif Vir Natuurwetenskap En Tegnologie / <i>South African Journal of Science and Technology</I&gt; 33 (1), 1 bladsy. https://doi.org/10.4102/satnt.v33i1.938.