1. D. T. Chivers, E. M. Rimmer, B. W. Allardyce, R. C. Witcomb, S. S. Domingo andN. W. Tanner:Nucl. Phys.,126 A, 129 (1969).
2. E. Bellotti, S. Bonetti, E. Fiorini, A. Pullia andM. Rollier:Preliminary results on interactions of low-energy pions on carbon nuclei, inHigh-Energy Physics and Nuclear Structure (New York, 1970), p. 461;E. Bellotti, S. Bonetti, D. Cavalli andE. Fiorini:Proceedings of the Topical Seminar on Interactions of Elementary Particles with Nuclei (Trieste, 1970), p. 369.
3. I. S. Shapiro:Rendiconti S.I.F., Course XXXVII (New York, 1967), p. 210.
4. V. S. Barashenkov andV. M. Maltsev:Cross-Sections of Elementary Particle Interactions (Moscow, 1966).
5. H. Tyren, S. Kullander, O. Sundberg, R. Ramachandran andP. Isacsson:Nucl. Phys.,79, 321 (1966).