1. For a general presentation of various aspects of the subject, including new results and references, see: Stapp, H.P.: Discontinuity formulas for multiparticle amplitudes. In: Structural analysis of collision amplitudes (eds. R. Balian, D. Iagolnitzer), p. 191. Amsterdam: North-Holland 1976
2. Iagolnitzer, D.: TheS-matrix, Chap. III. Amsterdam: North-Holland 1978
3. Iagolnitzer, D.: Macrocausality, unitarity and discontinuity formulae inS-matrix theory. Publ. RIMS, Kyoto Univ.12, Suppl. 89–112 (1977)
4. Stapp, H.P.: J. Math. Phys.9, 1548 (1968); Coster, J., Stapp, H.P.: J. Math. Phys.10, 371 (1969);11, 1441 (1970);11, 2743 (1970);16, 1288 (1975)
5. Bloxham, M.I.W., Olive, D.I., Polkinghorne, J.C.: J. Math. Phys.10, 494 (1969);10, 545 (1969);10, 553 (1969) See also earlier results in: Eden, R.J., Landshoff, P.-V., Olive, D.I., Polkinghorne, J.C.: The analyticS-matrix, Chap. 4. Cambridge: Cambridge University Press 1966