1. 1) N. Q. Minh: J. Am. Ceram. Soc., 76 (1993), 563.
2. 2) S. Majumdar, T. Claar and B. Flandermeyer: J. Am. Ceram. Soc., 69 (1986), 628.
3. 3) E. I. Tifée, W. Wersing, M. Schessl and H. Greiner: Ber. Bunsenges, Phys. Chem., 94 (1990), 978.
4. 4) J. Hartivigsen, S. Elangovan and A. Kandkar: SIENCE AND TECHNOLOGY OF ZIRCONIA V, ed. by S.P.S. Badwall, M. J. Bannister and R. H. J. Hannink: Lancaster, Basel, (1993), p. 682.
5. 5) H. Karoliussen, K. Nisancioglu, A. Solheim and R. Odeg.ard: Proc. of the third international symposium on SOLID OXIDE FUEL CELLS, ed. by S. C. Singhal and H. Iwahara: Honolulu, Hawaii, (1993), p. 868.