1. V. I. Vysotskii, V. I. Vorontsov, and R. N. Kuz’min, Pis’ma Zh. Tekh. Fiz. 10, 300 (1984) [Sov. Tech. Phys. Lett. 10, 126 (1984)].
2. V. I. Vysotskii, Phys. Rev. C 58, 337 (1998).
3. V. I. Vysotskii, V. P. Bugrov, A. A. Kornilova, et al., Hyperfine Interact. 107, 277 (1997).
4. V. I. Vysotskii, A. A. Kornilova, A. A. Sorokin, et al., Laser Phys. 11, 442 (2001).
5. V. F. Masterov, S. I. Bondarevskii, V. V. Eremin, et al., Fiz. Tverd. Tela (St. Petersburg) 40, 1832 (1998) [Phys. Solid State 40, 1661 (1998)].