1. C. Jarlskog et al., Phys. Rev. D 8 (1973) 3813.
2. Quantum Electrodynamics, Advanced series on directions in high energy physics, Vol. 7, Ed. T. Kinoshita, World Scientific, 1990.
3. J. Bailey et al., Nucl. Phys. 150B (1979) 1; J. Calmet et al., Rev. Mod. Phys. 49 (1977) 21.
4. Y. Sakurayama, H. Salecker, Z. Phys. C 51 (1991) 403, and references therein.
5. P. Raychaudhuri and P. Bandyopadhyay, Phys. Rev. D 3, 1378 (1971); P. Raychaudhuri Physics. Essays 2, 339 (1989).