1. See, for instance,G. Preparata:Why are quark (and gluons) confined? MITH 93/18, Milano, June 1993, Preprint, to appear in theProceedings of the VIII Winter School on «Hadronic Physics» — Folgaria, 1–6 February 1993.
2. G. K. Savvidy:Phys. Lett. B,71, 133 (1977).
3. G. Preparata:Nuovo Cimento A,96, 366 (1986).
4. E142Collaboration P. L. Anthony (et al.):Determination of the neutron structure function, SLAC-PUB-6101 (1993), preprint.
5. SMCCollaboration (B. Adeva et al.):Phys. Lett. B,302, 533 (1993).