1. S.L. Glashow, Nucl. Phys. 22 (1961) 579
2. S. Weinberg, Phys. Rev. Lett. 19 (1967) 1264
3. A. Salam, in Elementary Particle Theory, ed. N. Svartholm (Almquist and Wiksells, Stockholm, 1969), p. 367.
4. F. Englert, R. Brout, Phys. Rev. Lett. 13, 321 (1964); P.W. Higgs, Phys. Lett. 12,132 (1964).
5. E.D.Commins, Weak interactions, Mc Graw Hill, 1973; L. V. Okun, Leptons and Quarks, North Holland, 1982; D. Bailin, Weak Interactions, 2nd e., Hilger, 1982; H. M. Georgi, Weak interactions and modern particle theory, Benjamin, 1984.