1. Swiss Academy of Engineering Sciences, Seltene Metalle—Rohstoffe fur Zukunftstechnologien [Rare Metals—Raw Materials for Future Technologies] (Zurich, Switzerland: Swiss Academy of Engineering Sciences, 2010), www.satw.ch/publikationen/schriften/SelteneMetalle.pdf .
2. U.S. Geological Surveys, Mineral Commodity Summaries 2013 (Reston, VA: U.S. Geological Surveys, 2013), www.minerals.usgs.gov/minerals/pubs/mcs/2013/mcs2013.pdf .
3. J. Matthey, Market Data Tables (Hertfordshire, U.K.: Johnson Matthey Precious Metals Management), www.platinum.matthey.com/publications/market-data-tables .
4. D. Merriman, Royal Society of Chemistry Environmental Chemistry Group 2013—A Review of the Global Supply of Rare Earths (London, U.K.: Roskill Consulting Group Ltd., 2013), www.rsc.org/images/David-Merriman_tcm18-230229.pdf .
5. C. Hagelüken, Paper presented at 3rd European Workshop on Spent Catalysts, (Berlin, Germany, 8–9 February 2006).