1. E. L. Belokoneva, M. A. Simonov, A. V. Butashin, et al., Dokl. Akad. Nauk SSSR 255, 1099 (1980) [Sov. Phys. Dokl. 25, 954 (1980)].
2. B. V. Mil’, A. V. Butashin, A. M. Éllern, and A. A. Maier, Izv. Akad. Nauk SSSR, Neorg. Mater. 17, 1648 (1981).
3. I. A. Andreev and M. F. Dubovik, Pis’ma Zh. Tekh. Fiz. 10, 487 (1984) [Sov. Tech. Phys. Lett. 10, 205 (1984)].
4. E. L. Belokoneva, S. Yu. Stefanovich, Yu. V. Pisarevskii, and A. V. Mogunov, Zh. Neorg. Khim. 45, 1786 (2000).
5. B. V. Mill and Yu. V. Pisarevsky, in Proceedings of the International IEEE Frequency Control Symposium, Kansas City, 2000, p. 133.