1. P. Kofstad, “Nonstoichiometry Diffusion and Electrical Conductivity in Binary Metal Oxides”, ( Wiley, New York ) (1972).
2. R. Lindner and Å. Åkerstrøm, Z. Phys. Chem. N.F., 6:162 (1956).
3. W.C. Hagel and A.U. Seybolt, J. Electrochem. Soc., 108:1146 (1961).
4. L.C. Walters and R.E. Grace, J. Appl. Phys., 8:2331 (1965).
5. P. Kofstad and K.P. Lillerud, J. Electrochem. Soc., 127:2410 (1980).