1. D. Diakonov and M. Éídes, Pis’ma Zh. Éksp. Teor. Fiz. 38(7), 358 (1983) [JETP Lett. 38 (7), 433 (1983)]; J. Balog, Phys. Lett. B 149, 197 (1984); A. Andrianov, V. Andrianov, Yu. Novozhilov, and V. Novozhilov, Lett. Math. Phys. 11, 217 (1986); Phys. Lett. B 186, 401 (1987); Phys. Lett. B 203, 160 (1988); V. Andrianov and V. Novozhilov, Yad. Fiz. 43, 983 (1986) [Sov. J. Nucl. Phys. 43, 626 (1986)].
2. G. Adkins, C. Nappi, and E. Witten, Nucl. Phys. B 228, 552 (1983); V. Kopeliovich, Yad. Fiz. 47, 1495 (1988) [Sov. J. Nucl. Phys. 47, 949 (1988)]; E. Braaten and L. Carson, Phys. Rev. D: Part. Fields 38, 3525 (1988); P. Irwin, Phys. Rev. D 61, 114024 (2000); S. Krusch, Ann. Phys. (Weinheim) 304, 103 (2003); Proc. R. Soc. London, Ser. A 462, 2001 (2006).
3. O. V. Manko, N. S. Manton, and S. W. Wood, Phys. Rev. C: Nucl. Phys. 76, 055 203 (2007).
4. V. Kopeliovich, A. Shunderuk, and G. Matushko, Yad. Fiz. 69(1), 124 (2006) [Phys. At. Nucl. 69 (1), 120 (2006)]; V. Kopeliovich and A. Shunderuk, Eur. Phys. J. A 33, 277 (2007).
5. E. Guadagnini, Nucl. Phys. B 236, 35 (1984).