1. R. Ammar, R. Levi Setti, S. Limentani, P. E. Schlein, W. E. Slater andP. H. Steinberg:Annual Intern. Conf. on High Energy Physics at CERN (1958);
2. R. H. Dalitz andM. Kaplon:Reports, pp. 181, 200.
3. W. E. Slater:Suppl. Nuovo Cimento,10, 1 (1958).
4. We are greatly indebted to Dr.W. H. Barkas for the loan of this stack (Berkeley 1 U).
5. P. C. Giles: UCRL Report no. 8007 (1957).