1. Aharonov, Y., Anandan, J., Popescu, S., & Vaidman, L.: 1990, Phys. Lett., 64, 2965
2. Cirac, J. I., & Zoller, P.: 1995, Phys. Rev. Lett., 74, 4091
3. Cramer, J. G.: 1986, Rev. Mod. Phys., 58, 647
4. Davies, P. C. W.: 1974, The Physics of Time-Asymmetry. University of California Press
5. Elitzur, A. C.: 1991, Found. Phys. Lett., 3, 525