1. O. Nachtmann: “Non perturbative QCD Effects in High Energy Collisions”, Heidelberg preprint, HD-THEP-94-42, Talk presented at the 18th Johns Hopkins Workshop, Florence, 1994
2. A. Donnachie, P.V. Landshoff: Phys. Lett. B296 (1992)
3. J. Dias de Deus: Lett. Nuovo Cimento, 5 (1972) 269
4. E.M. Levin, L.L. Frankfurt: JETP Lett. 2 (1965) 2; H. J. Lipkin, F. Scheck: Phys. Rev. Lett. 16 (1966) 71
5. P.D.B. Collins: “An Introduction to Regge Theory”, Cambridge University Press, Cambridge, U.K., 1977