Yttrium and all lanthanides except Ce, Pm, Eu, Tm, Yb 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.
Mosander C.G. (اکتبر ۱۸۴۳). «On the new metals, Lanthanium and Didymium, which are associated with Cerium; and on Erbium and Terbium, new metals associated with Yttria». Philosophical Magazine Series 3. ۲۳ (۱۵۲): ۲۴۱–۲۵۴. doi:10.1080/14786444308644728.
Georges, Audi; Bersillon, O. ; Blachot, J. ; Wapstra, A.H. (دسامبر ۲۰۰۳). «The Nubase evaluation of nuclear and decay properties». Nuclear Physics A. ۷۲۹ (۱): ۳–۱۲۸. doi:10.1016/j.nuclphysa.2003.11.001.نگهداری یادکرد:نامهای متعدد:فهرست نویسندگان (رده)
