1. See, for example:P. D. B. Collins andE. J. Squires:Regge Poles in Particle Physics, Springer Tracts in Modern Physics, Vol.45 (Berlin, 1968);J. Hamilton:Pion-Nucleon Interactions, inHigh-Energy Physics, Vol.1, edited byE. H. S. Burhop (New York, 1967), p. 183.
2. J. Baacke andF. Steiner:Fortschr. Phys.,18, 67 (1970).
3. R. Oehme:Phys. Rev.,100, 1503 (1955);102, 1174 (1956); see also:R. H. Capps andG. Takeda:Phys. Rev.,103, 1877 (1956);G. F. Chew, M. Goldberger, F. E. Low andY. Nambu:Phys. Rev.,106, 1337 (1957);L. D. Solovyov:Nucl. Phys.,5, 256 (1958);K. Dietz andG. Höhler:Zeits. Phys.,160, 453 (1960);M. Carrassi andG. Passatore:Nuovo Cimento,26, 1254 (1962);27, 1156 (1963).
4. For πN → πN:F. Steiner: unpublished (1967);J. Baacke, G. Höhler andF. Steiner:Zeits. Phys.,221, 134 (1969);J. Baacke andF. Steiner:Fortschr. Phys.,18, 67 (1970);F. Steiner:Fortschr. Phys.,18, 43 (1970). For photo- and electroproduction:W. Schmidt andG. Schwiderski:Fortschr. Phys.,15, 393 (1967);F. A. Berends, A. Donnachie andD. L. Weaver:Nucl. Phys.,4 B, 1 (1968);G. von Gehlen:Nucl. Phys.,9 B, 17 (1969). For ππ → ππ:S. M. Roy:Phys. Lett.,36 B, 353 (1971);J. L. Basdevant, J. C. Le Guillou andH. Navelet:Nuovo Cimento,7 A, 363 (1972).
5. F. Steiner:Fortschr. Phys.,18, 43 (1970).