1. Brown, P. H., Rathjen, A. H., Graham, R. D. et al., Rare earth elements in biological systems, in Handbook of Physics and Chemistry of Rare Earths (eds. Gschneider, K. A. Jr., Eyring, L.), Vol. 13, Amsterdam: Elsevier Science Publisher, 1990, 423.
2. Ni, J. Z., Bioinorganic chemistry of Rare Earth Elements (in Chinese), Beijing: Science Press, 1995.
3. Hirano, S., Suzuki, K. T., Exposure, metabolism and toxicity of rare earths and related compounds, Environmental Health Perspectives, 1996, 104(17): 85.
4. Sileio, A., Mauro, B., Lanthanide(III) chelates for NMR biomedical applications, Chemical Society Reviews, 1998, 27: 19.
5. Rath, C., Joseph, P. M., A comparison of beam-hardening artifacts in X-ray computerized tomography with gadolinium and iodine contrast agents, Medical Physics (Woodbury), 1995, 22(12): 1977.