↑ 4.04.14.24.3Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN978-1-62708-155-9.
↑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 (sa wikang Ingles). 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.
↑Chen, Xin; atbp. (2019-12-13). "Lanthanides with Unusually Low Oxidation States in the PrB3– and PrB4– Boride Clusters". Inorganic Chemistry (sa wikang Ingles). 58 (1): 411–418. doi:10.1021/acs.inorgchem.8b02572. PMID30543295.