1. R. B. Griffiths,J. Stat. Phys. 36, 219 (1984).
2. R. B. Griffiths,Am. J. Phys. 55, 11 (1987).
3. R. B. Griffiths inFundamental Questions in Quantum Mechanics, L. M. Roth and A. Inomata, eds. (Gordon & Breach, New York, 1986), p. 211; inNew Techniques and Ideas in Quantum Measurement Theory, D. M. Greenberger, ed. (New York Academy of Sciences, New York, 1986), p. 512.
4. R. Omnès,J. Stat. Phys. 53, 893 (1988) and items cited in Ref. 5.
5. R. Omnès,Rev. Mod. Phys. 64, 339 (1992).