1. Smiltens, J.: J. Chem. Phys. 20, 990 (1952)
2. Bruni, F. J., Brundage, W. E.: J. Cryst. Growth 19, 5 (1973)
3. Sugimoto, M.: Japan J. Appl. Phys. 5, 557 (1966)
4. Sugimoto, M.: Proceedings of Int. Conf. on Ferrites, Univ. of Tokyo Press 1971, 318
5. Kobayashi, S., Yamagishi, I., Ishii, R., Sugimoto, M.: Proceedings of Int. Conf. on Ferrites, Univ. of Tokyo Press 1971, 326