1. 1) C. Wood: Rep. Prog. Phys. 51 (1988) 459–539.
2. 2) B. J. Beaudry and K. A. Gschneidner, Jr.: CRC Handbook of Thermoelectrics, ed. by D. M. Rowe, (CRC Press, Boca Raton, 1995) pp. 339–348.
3. 3) M. Ohta, S. Hirai, H. Kato, T. Nishimura and Y. Uemura: Appl. Phys. Lett. 87 (2005) 042106-1–042196-3.
4. 4) G. V. Samsonov: High-Temperature Compounds of Rare Earth Metals with Nonmetals, (Consultants Bureau, New York, 1965) pp. 211–279.
5. 5) G. V. Samsonov and S. V. Drozdova: Sulfides, (Metallurgy, Moscow, 1972) (in Russian) [Japanese Translation: Ryukabutu Binran, (Nisso Tsushin, Wakayama, 1974) pp. 58–115].