1. A. M. Kosevich, B. A. Ivanov, and A. S. Kovalev, Nonlinear Magnetization Waves. Dynamic and Topological Solitons [in Russian], Naukova Dumka, Kiev (1983).
2. A. M. Kosevich, B. A. Ivanov, and A. S. Kovalev, Phys. Rep. 194, 117 (1990).
3. A. I. Akhiezer, V. G. Bar’yakhtar, and S. V. Peletminskii, Spin Waves, Interscience, New York (1968).
4. A. M. Kosevich, Physica D 119(1–2), 134 (1998).
5. V. I. Karpman and E. Maslov, Zh. Éksp. Teor. Fiz. 73, 537 (1977) [Sov. Phys. JETP 46, 281 (1977)].