1. B. Pietrzyk, in the proceedings of the XXIXth Rencontres de Moriond, March 1994, preprint LAPP-EXP-94.07 (hep-ex/9406001)
2. The SLD Collaboration, F. Abe et al., preprint SLAC-PUB-6456, to appear in Physical Review Letters; M. Woods, ibid, preprint SLAC-PUB-6493
3. J. Erler, preprint UPR-069T (hep-ph/9406429)
4. B. Lynn, M. Peskin, R. Stuart, in Physics at LEP vol. 1, CERN Report 86-02, pp. 90?152
5. M.E. Peskin and T. Takeuchi, Phys. Rev. Lett. 65 (1990 964; Phys. Rev. D46 (1992) 381