1. BGS. Rare earth elements profile. British Geological Survey, 2011. 54p. http://www.bgs.ac.uk/ (accessed July 2016).
2. USGS. Rare earths. Mineral Commodity Summaries – U.S. Geological Survey, 2019. pp. 132–3. http://minerals.usgs.gov/minerals/pubs/commodity/rare_earths/mcs-2019-raree.pdf (accessed March 2019).
3. Rare earth elements as critical raw materials: focus on international markets and future strategies;Massari;Resour Policy,2013
4. Rare earths supply chains: current status, constraints and opportunities;Golev;Resour Policy,2014
5. MME. Plano Nacional de Mineração 2030 (PNM – 2030), Ministério das Minas e Energia – MME, Secretaria de Geologia, Mineração e Transformação Mineral – SGM, 2010. 157p. http://www.mme.gov.br/web/guest/secretarias/geologia-mineracao-e-transformacao-mineral/plano-nacional-de-mineracao-2030/pnm-2030 (accessed July 2016).