1. J. Zhang, R. Wang, J. Bai, and S. Wang, J. Rare Earths 20, 449 (2002).
2. J. Zhang, R. Wang, and H. Yang, Chin. J. Anal. Chem. 31, 472 (2003).
3. Y. Hasegawa and T. Nakanishi, RSC Adv. 5, 338 (2015).
4. J.-C. G. Bunzli and S. V. Eliseeva, Chem. Sci. 4, 1913 (2013).
5. K. Binnemans, in Handbook on the Physics and Chemistry of Rare Earths (Elsevier, Amsterdam, 2005), Vol. 35, p. 107.