1. For literature see: Wheeler, J.A., Zurek, W.A.: Quantum theory and measurement. Princeton: Princeton University Press 1983
2. Weizs�cker, C.F. von. Z. Phys.70, 114 (1931)
3. Wheeler, J.A.: In: Mathematical foundations of quantum theory The past and the delayed-choice double-slit experiment. Marlow, A.R. (ed.), p. 9. New York: Academic Press 1978
4. Miller, W.A., Wheeler, J.A.: Delayed-choice experiments and Bohr's elementary quantum phenomenon. In: Proceedings of the 2nd International Symposium on Foundations of Quantum Mechanics, Tokyo 1986. Namiki, M., Ohnuki, Y., Murayama, Y., Nomura, S. (eds.), p. 140. Kokubunji, Tokyo, Japan: Physical Society of Japan 1987
5. Hellmuth, T., Walther, H., Zajonc, A., Schleich, W.: Phys. Rev.35A (No. 6), 2532 (1987)