1. Phosphates and Phosphoric Acid; Raw Materials, Technology, and Economics of the Wet Process;Becker,1989
2. Ion exchange in uranium extraction;Streat,1987
3. E.T.M.J. Martynowicz, Impurity Uptake in Calcium Sulfate during Phosphoric Acid Processing. PhD Thesis, Delft University of Technology, The Netherlands, 1994.
4. Growth of gypsum III. Influence and incorporation of lanthanide and chromium ions;de Vreugd;J. Cryst. Growth,1994
5. Ion Exchange;Helfferich,1995