1. I. A. Shaikevich, P. I. Drozd, and L. V. Poperenko, Vestn. Kiev. Univ. Fiz., No. 25, 39?49 (1984).
2. Karl A. Gschneidner (ed.), Handbook on the Physics and Chemistry of Rare Earths. Vol. 1, Metals, North-Holland, Amsterdam (1978), p. 335.
3. V. P. Shirokovskii, M. M. Kirillova, and N. A. Shilkova, Zh. Éksp. Teor. Fiz., No. 3, 784?791 (1982).
4. M. M. Noskov, Optical and Magnetooptical Properties of Metals [in Russian], Ural Scientific Center, Academy of Sciences of the USSR (1983).
5. S. C. Keeton and T. L. Lousks, Phys. Rev.,168, No. 3, 672?678 (1968).