1. H.G. von Schnering, Nova Acta Leopoldina 59 (1985) 168.
2. J. Llanos, Ph.D. Thesis, University of Stuttgart, 1984.
3. B. Eisenmann, H. Schäfer, R. Zahler, J. Less-Common Met. 118 (1986) 43.
4. H. Anno, M. Hokazono, M. Kawamura, J. Nagao, K. Matsubara, in: Proceedings of the 21st International Conference on Thermoelectrics, IEEE, New York, NY, 2002, p. 77.
5. W. Carrillo-Cabrera, S. Paschen, Yu. Grin, J. Alloys Compounds 333 (2002) 4.