1. E W Kolb and M S Turner The Early Universe (New York: Addison-Wesley Pub. Co.) (1990)
2. F S Navarra et al., Phys. Rev. C45 2552 (1992)
3. R D Field Application of Perturbative QCD (New York: Addison-Wesley Pub. Co.) (1989)
4. B L Combridge Nucl. Phys. B151 429 (1979)
5. J D Bjorken Phys. Rev. D27 140 (1983)