1. On the Connection between Phase Shifts and Scattering Potential
2. Postdeadline paper W-10 presented at 7th International Conference on Quantum Electronics;Grieneisen,1972
3. paper W1-3 at 3rd Rochester Conference on Coherence and Quantum Optics,1972
4. Further experimental results have been reported by Hahn, E.L., paper P-1 at Montreal meeting and paper Wl-1 at Rochester meeting.