Coba jelasin Lihat Juga dari Logam tanah jarang dong

Gordon B. Haxel, James B. Hedrick, and Greta J. Rare Earth Elements—Critical Resources for High Technology http://minerals.usgs.gov/minerals/pubs/commodity/rare_earths/. US Geological Survey

W., Christopher. S. Study of the Rare Earth Resources and Markets for the Mt. Weld Complex. Washingon: BBC Research.