1. A. Frank, P. Van Isacker, and J. Gomez-Camacho, Phys. Lett. B 582, 15 (2004).
2. Yu. Alexandrov, JINR preprint E3-2006-142.
3. Yu. Pokotilovski, Yadernaya Fiz. 69, 924 (2006).
4. L. D. Landau, A. I. Akhiezer, and E. M. Lafshitz, Course of General Physics (Moscow, 1965).
5. V. E. Krohn and G. R. Ringo, Phys. Rev. 148, 1303 (1966).