1. M. Felcini, hep-ex/9907049.
2. Talks given at LEPC, November 9, 1999: ALEPH Collaboration, A. Blondel, http://alephwww.cern.ch/ALPUB/seminar/lepc_nov99/lepc.pdf;
3. DELPHI Collaboration, J. Marco, http://axsant01.cern.ch/lepc;
4. L3 Collaboration, G. Rahal-Callot, http://l3www.cern.ch/conferences/ps/Rahal_LEPC_L3_Nov99.ps.gz;
5. OPAL Collaboration, P. Ward, http://www.cern.ch/Opal/talks/pward_lepc99.ps.gz.