1. S.L. Glashow, Nuc. Phys. 22 (1961) 579.
2. S. Weinberg, Phys. Rev. Lett. 19 (1967) 1264.
3. A. Salam, in “Elementary Particle Theory”, ed. W. Svartholm, Almquist and Wiksell, Stockholm (1968).
4. C. Rubbia et al., Proc. Int. Conf. on Neutrinos, Aachen, 1976. ed. H. Faissner et al., (Kreweg and Braunschweig), 683.
5. G. Altarelli et al., Z. Phys. C27 (1985) 617. For more recent evaluations including partial 0(α
s
3
corrections, see for example T. Matsuura et al., Nucl. Phys. B319 (1989) 570. K. Ellis, Proceeding 8th Topical Workshop in pp Collider Physics, Castiglione, Italy (1989). To be published.