Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (2003-12-15). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.
Chen, Xin; et al. (13 Desember 2019). "Lanthanides with Unusually Low Oxidation States in the PrB3– and PrB4– Boride Clusters". Inorganic Chemistry. 58 (1): 411–418. doi:10.1021/acs.inorgchem.8b02572. PMID30543295.
Brauer, G.; Pfeiffer, B. (1963). "Hydrolytische spaltung von höheren oxiden des Praseodyms und des terbiums". Journal of the Less Common Metals. 5 (2): 171–176. doi:10.1016/0022-5088(63)90010-9.
Weeks, Mary Elvira (1932). "The Discovery of the Elements: XI. Some Elements Isolated with the Aid of Potassium and Sodium:Zirconium, Titanium, Cerium and Thorium". The Journal of Chemical Education. 9 (7): 1231–1243. Bibcode:1932JChEd...9.1231W. doi:10.1021/ed009p1231.
Suseelan Nair, K.; Mittal, M. C. (1988). "Rare Earths in Magnesium Alloys". Materials Science Forum. 30: 89–104. doi:10.4028/www.scientific.net/MSF.30.89.Parameter |s2cid= yang tidak diketahui akan diabaikan (bantuan)
Borchert, Y.; Sonstrom, P.; Wilhelm, M.; Borchert, H.; et al. (2008). "Nanostructured Praseodymium Oxide: Preparation, Structure, and Catalytic Properties". Journal of Physical Chemistry C. 112 (8): 3054. doi:10.1021/jp0768524.
Overland, Indra (1 Maret 2019). "The geopolitics of renewable energy: Debunking four emerging myths". Energy Research & Social Science. 49: 36–40. doi:10.1016/j.erss.2018.10.018. ISSN2214-6296.
Pol, Arjan; Barends, Thomas R. M.; Dietl, Andreas; Khadem, Ahmad F.; Eygensteyn, Jelle; Jetten, Mike S. M.; Op Den Camp, Huub J. M. (2013). "Rare earth metals are essential for methanotrophic life in volcanic mudpots". Environmental Microbiology. 16 (1): 255–64. doi:10.1111/1462-2920.12249. PMID24034209.
Kang, L., Shen, Z. & Jin, C. Neodymium cations Nd3+ were transported to the interior of Euglena gracilis 277. Chin.Sci.Bull.45, 585–592 (2000). https://doi.org/10.1007/BF02886032
Weeks, Mary Elvira (1932). "The Discovery of the Elements: XI. Some Elements Isolated with the Aid of Potassium and Sodium:Zirconium, Titanium, Cerium and Thorium". The Journal of Chemical Education. 9 (7): 1231–1243. Bibcode:1932JChEd...9.1231W. doi:10.1021/ed009p1231.
Chen, Xin; et al. (13 Desember 2019). "Lanthanides with Unusually Low Oxidation States in the PrB3– and PrB4– Boride Clusters". Inorganic Chemistry. 58 (1): 411–418. doi:10.1021/acs.inorgchem.8b02572. PMID30543295.
Pol, Arjan; Barends, Thomas R. M.; Dietl, Andreas; Khadem, Ahmad F.; Eygensteyn, Jelle; Jetten, Mike S. M.; Op Den Camp, Huub J. M. (2013). "Rare earth metals are essential for methanotrophic life in volcanic mudpots". Environmental Microbiology. 16 (1): 255–64. doi:10.1111/1462-2920.12249. PMID24034209.
osti.gov
"Phase Diagrams of the Elements", David A. Young, UCRL-51902 "Prepared for the U.S. Energy Research & Development Administration under contract No. W-7405-Eng-48".
Overland, Indra (1 Maret 2019). "The geopolitics of renewable energy: Debunking four emerging myths". Energy Research & Social Science. 49: 36–40. doi:10.1016/j.erss.2018.10.018. ISSN2214-6296.