1. B. S. VanGosen , P. L.Verplank , K. R.Long , J.Gambogi and R. R.Seal II , The rare-earth elements—vital to modern technologies and lifestyles , Report U.S. Geological Survey Fact Sheet 2014–3078 , USGS Mineral Resources Program , Reston, VA , 2014
2. G. B. Haxel , J. B.Hedrick and G. J.Orris , Rare Earth Elements—Critical Resources for High Technology , Report U.S. Geological Survey Fact Sheet 087–02 , USGS Mineral Resources Program , Reston, VA , 2002
3. K. R. Long , B. S.VanGosen , N. K.Foley and D.Cordier , The principal rare earth elements deposits of the United States—a summary of domestic deposits and a global perspective , Report U.S. Geological Survey Scientific Investigations Report 2010–5220 , U.S. Geological Survey , Reston, VA , 2010
4. T. G. Goonan , Rare earth elements—end use and recyclability , Report U.S. Geological Survey Scientific Investigations Report 2011-5094 , U.S. Geological Survey , Reston, VA , 2011
5. E. Walton and T.White , Rare Earth Element Interferences in Collision Cell and Standard Mode ICP-MS Analyses of Arsenic and Selenium , 2015 , https://www.epa.gov/sites/production/files/2015-10/documents/rare_earth_interferences_on_icp-ms_analysis_of_arsenic_oct2015.pdf , accessed July 9, 2018