1. V. S. Kuz’min and G. G. Fedoruk, Nonsteady-State Coherent Phenomena in Paramagnetic Spin Systems [in Russian], Bel. Gos. Univ., Minsk (2001).
2. V. M. Akulin and N. V. Karlov, Intense Resonant Interactions in Quantum Electronics [in Russian], Nauka, Moscow (1987).
3. M. I. Kurkin and E. A. Turov, NMR in Magnetically Ordered Materials and Its Application [in Russian], Nauka, Moscow (1990).
4. A. S. Borovik-Romanov, Yu. M. Bun’kov, B. S. Dumesh et al., Usp. Fiz. Nauk, 142, 537–570 (1984).
5. K. Steenbeck, T. Eich, K. Kirsch, K. O’Donnell, and E. Steinbeiss, Appl. Phys. Lett., 71, 968–970 (1997).