1. Critical Materials Strategy;Bauer,2010
2. Critical Materials Strategy;Bauer,2011
3. The potential scarcity of rare elements for the Energiewende;Bradshaw;Green,2013
4. Risk List 2012: Current Supply Risk Index for Chemical Elements or Element Groups Which are of Economic Value;British Geological Survey,2012
5. Critical Metals for Future Sustainable Technologies and Their Recycling Potential;Buchert,2009