1. For a review of the phenomenology ofE 6 superstring-inspired models see J.L. Hewett, T.G. Rizzo: Univ. of Wisconsin report MAD/PH/446 (1988), to appear in Phys. Rep.
2. D. Schaile, P.M. Zerwas: in Proceedings of the Workshop on Physics at Future Accelerators, CERN yellow report 87-07, Vol. II, p. 251 (1987)
3. E.N. Argyes, C.G. Papadopoulos, S.D.P. Vlassopulos: Phys. Lett. 202B (1988) 425; V.D. Angelopoulos et al.: Nucl. Phys. B292 (1987) 59
4. For a general discussion of the effective gauge boson approximation see P.W. Johnson, F. Olness, W.-K. Tung: Proceedings of the 1986 Summer Study on the Physics of the Superconducting Supercollider, R. Donaldson, J. Marx (eds.) (1986)
5. The author would like to thank Manuel Drees for extensive discussions related to the importance of the QCD background in the case of singleD production coming from the hadronic structure of the photon