1. See the contributions of H. Anderson and J. Van der Velde to this Seminar.
2. The first ideas on the massive quark model (MQM) date back to 1972, and were first published in G. Preparata, Phys. Rev. D 2973 (1973).
3. The most comprehensive description of the MQM is contained in G. Preparata, A possible way to look at hadrons; the MQM, in Lepton hadron structure (ed. A. Zichichi) (Academic Press, NY, 1975 ), p. 54.
4. P. Castorina, G. Nardulli and G. Preparata, A realistic description of deep inelastic structure functions, preprint CERN TH 2670 (1979).
5. G. Preparata, Phys. Lett. 36B, 56 (1972).