1. A.D. Martin, T.D. Spearman: Elementary particle theory. Amsterdam: North-Holland 1969; H. Pilkuhn: The interaction of hadrons. Amsterdam: North-Holland 1969; H. Burchard: Dispersion relation Dynamics. Amsterdam: North-Holland 1969; F. Zachariasen, C. Zemach: Phys. Rev.128, 849 (1962)
2. R.L. Jaffe, F.E. Low: Phys. Rev.D19, 2105 (1979); E. van Beveren, C. Dullemond, T.A. Rijken: Z. Phys. C — Particles and Fields19, 275 (1983)
3. B. Hyams et al.: Nucl. Phys.B64, 134 (1973); P. Estabrooks, A.D. Martin: Nucl. Phys.B79, 301 (1974)
4. M. Roos: Nucl. Phys.B97, 165 (1974)
5. V.K. Khenner: Yad. Phys.27, 1052 (1978);31, 193 (1980);31, 424 (1980); B. Costa: Phys. Lett.67B, 213 (1977)