1. Gridnev, S.A., Soros. Obrazov. Zh., 2000, vol. 6, no. 8, pp. 100–107.
2. Grenet, J.-C. and Poix, P., J. Solid State Chem., 1976, vol. 17, pp. 107–111.
3. Grenet, J.-C, Berthon, I, and Poix, P., J. Solid State Chem., 1977, vol. 22, pp. 411–417.
4. Maeno, Y., Hashimoto, H., and Yoshida, K., Nature, 2002, vol. 372, pp. 532–534.
5. Grenet, J.-C., Poix, P., and Michel, A., Ann. Chim. (Paris), 1972, vol. 1972, pp. 231–234.