1. K. Gottfried, Proc. HEP-83, Brighton (UK), eds. J. Guy and C. Costain (1983).
2. P.M. Tuts, Proc. Lepton Photon Symp., Cornell University, eds. D.G. Cassel and D.L. Kreinick (1983)
3. See, for instance, K. Berkelmann, Phys. Rep. 98C:145 (1983)
4. J. Lee Franzini and P. Franzini, Ann. Rev. Nucl. Part. Sci 33:1 (1983)
5. E.D. Bloom and C.W. Peck, ibid. 33:143 (1983).