1. See, for example,Proceedings of the International Symposium on the Foundations of Quantum Mechanics, edited byS. Kamefuchi et al. (Phys. Soc. Japan, Tokyo, 1984);Proceedings of the 2nd International Symposium on the Foundations of Quantum Mechanics, edited byM. Namiki et al. (Phys. Soc. Japan, Tokyo, 1987);Proceedings of the 3rd International Symposium on the Foundations of Quantum Mechanics, edited byS. Kobayashi et al. (Phys. Soc. Japan, Tokyo, 1990).
2. S. Machida andM. Namiki:Prog. Theor. Phys.,63, 1457, 1833 (1980);M. Namiki:Found. Phys.,18, 29 (1988).
3. H. Hepp:Helv. Phys. Acta,45, 237 (1972).
4. R. Fukuda:Prog. Theor. Phys.,81, 34 (1989).
5. T. Kobayashi andK. Ohmomo:Phys. Rev. A,41, 5798 (1990).