1. Kido, J. and Okamoto, Y., Chem. Rev., 2002, vol. 102, no. 6, p. 2357.
2. Werts, H.V.M., Sci. Prog., 2005, vol. 88, no. 2, p. 101.
3. Binnemans, K., Handbook of the Physics and Chemistry of Rare-Earths, Gschneidner, K.A., Bunzli, J.G., and Pecharsky, V.K., Eds., New York: Elsevier, 2005, vol. 35, p. 107.
4. Taydakov, I.V. and Krasnosel’skii, S.S., Khim. Geterotsikl. Soedin., 2011, no. 6, p. 843.
5. Taydakov, I.V., Zaitsev, B.E., Krasnosel’skii, S.S., et al., Russ. J. Inorg. Chem., 2011, vol. 56, no. 3, p. 345.