1. E.W. Kolb, M.S. Turner, The Early Universe, Addison-Wesley, Reading, MA, 1989.
2. G.'t Hooft, Phys. Rev. Lett. 37 (1976) 8; V.A. Kuzmin, V.A. Rubakov, M.E. Shaposhnikov, Phys. Lett. B 155 (1985) 36.
3. D. Brahm, in: Proc. XXVI Int. Conf. High Energy Physics, Dallas, Texas, August 1992; M.E. Shaposhnikov, Nucl. Phys. B 287 (1987) 757; B 299 (1988) 797; V.A. Rubakov, M.E. Shaposhnikov, Usp. Fiz. Nauk 166 (1996) 493.
4. M.E. Shaposhnikov, Nucl. Phys. B 287 (1987) 757; B 299 (1988) 797; N. Turok, J. Zadrozny, Phys. Rev. Lett. 65 (1990) 2331; A. Kazarian, S. Kuzmin, M.E. Shaposhnikov, Phys. Lett. B 276 (1992) 131; L. McLerran, M.E. Shaposhnikov, N. Turok, M. Voloshin, Phys. Lett. B 256 (1991) 451.
5. A.I. Bochkarev, S.V. Kuzmin, M.E. Shaposhnikov, Phys. Lett. B 244 (1990) 275; M. Dine, P. Huet, R. Singleton Jr., Nucl. Phys. B 375 (1992) 625; M.E. Shaposhnikov, Phys. Lett. B 316 (1993) 112.