1. E. W. Kolb and M. S. Turner, ?The Early Universe? (Addison-Wesley, Redwood City, California, 1990); B. Sadoulet et al. Ann. Rev. Nucl. and Part. Sci. 38 (1988) 751
2. M. W. Goodman and E. Witten, Phys. Rev. D 31 (1985) 3059
3. T. Shutt et al. Phys. Rev. Lett. 69 (1992) 3531; 69 (1992) 3452
4. P. Pari, Mémoire, Conservatoire National des Arts et Métiers, Paris (1987), unpublished.
5. IF1320 and IF4500 parts from Interfet Corp., 322 Gold Street, Garland Texas 75042