1. M. I. Kurkin and E. A. Turov, NMR in Magnetically Ordered Substances and Its Applications (Nauka, Moscow, 1990) [in Russian].
2. V. S. Kuz’min and G. G. Fedoruk, Nonstationary Coherent Phenomena in Paramagnetic Spin Systems (Belarus. Gos. Univ., Minsk, 2001) [in Russian].
3. V. N. Berzhanskiĭ, S. V. Kapel’nitskiĭ, V. S. Pokatilov, and S. N. Polulyakh, Fiz. Tverd. Tela (St. Petersburg) 44(1), 83 (2002) [Phys. Solid State 44 (1), 88 (2002)].
4. S. N. Polulyakh, N. A. Sergeev, and A. A. Shemyakov, Fiz. Tverd. Tela (St. Petersburg) 42(9), 1628 (2000) [Phys. Solid State 42 (9), 1675 (2000)].
5. V. O. Golub, V. V. Kotov, and A. N. Pogorelyi, Fiz. Tverd. Tela (St. Petersburg) 40(6), 1056 (1998) [Phys. Solid State 40 (6), 964 (1998)].