1. D. Keefe, L. T. Kerth, C. M. Noble, J. J. Thresher, W. A. Wenzel andT. F. Zipf:Dipion Mass Spectrum from π−-pCollisions at 4 GeV/c, Lawrence Radiation Laboratory Report UCRL-11468 (1964) (unpublished) andProceedings of the International Conference on High-Energy Physics (Dubna, 1964) (to be published).
2. L. W. Jones, D. Harting, W. Middelkoop, B. Zacharov, D. O. Caldwell, E. Bleuler andB. Elsner:Proceedings of the International Conference on High-Energy Physics (Dubna, 1964) (to be published); this experiment used incident π− of 12 and 18 GeV/c.
3. W. J. Fickinger, D. K. Robinson andE. O. Salant:Phys. Rev. Lett.,10, 457 (1963).
4. J. P. Baton, A. Berthelot, B. Deler, O. Goussu, M. Neveu-René, A. Rogozinski, F. Shively, V. Alles-Borelli, E. Benedetti, R. Gessaroli andP. Waloschek:Nuovo Cimento,35, 713 (1965).
5. V. Hagopian andW. Selove:Phys. Rev. Lett.,10, 533 (1963).