1. S. L. Glashow, “Gauge Theories and Experiments at High Energies,” Proceedings of the Twenty-First Scottish Universities Summer School in Physics 1980, St. Andrews, Scotland, eds. K. C. Bowler and D. G.Sutherland, p. 433.
2. B. Cabrera, Phys. Rev. Lett. 48 (1982) 1378.
3. B. Cabrera, M. Taber, R. Gardner and J. Bourg, Phys. Rev. Lett. 51 (1983) 1933.
4. M. E. Huber, B. Cabrera, M. A. Taber, and R. D. Gardner, Phys. Rev. Lett. 64 (1990) 835.
5. R. D. Gardner, B. Cabrera, M. E. Huber, M. A. Taber and J. Bourg, Phys. Rev. D44 (1991) 622.