1. At the prest time the existence of a possible resonance at m = 6 GeV/c4 remains unconfirmed. See D. C. Hom et al., Phys. Rev. Lett. 36, 1236 (1976).
2. J. H. Christenson et al., Phys. Rev. Lett. 25, 1523 (1970); ibid, Phys. Rev. D 8, 2016 (1973).
3. J. J. Aubert et al., Phys. Rev. Lett. 33, 1404 (1974).
4. J. E. Augustin et al., Phys. Rev. Lett. 33, 1406, 1453 (1974).
5. L. M. Lederman, Columbia University preprint (1974).