1. S. Jin, T. M. Tiefel and R. C. Sherwood, Phys. Rev.
B37 (1987) 7850.
2. P. De Rango, PhD thesis, University J. Fourier, Grenoble (1992).
3. S. J. KEATING, I. WEI and T. Y. CHIEN, in “Ceramic Superconductors II”, (American Ceramic Society, 1988) p. 43.
4. J. M. Dance, A. Tressaud, B. Chevalier, J. Darriet and J. Etourneau, Solid State Ion.
32-33 (1989) 1188.
5. B. LEPINE, PhD thesis, University Bordeaux I (1990).