1. OPAL collaboration, Phys.Lett.B 374 (1996) 341.
2. Review of particle properties;Hernandez;Phys. Lett. B,1990
3. Review of particle properties;Hagiwara;Phys. Rev. D,2002
4. See, for example, A.Pich, FTUV/00-1214, hep-ph/0012297, December 2000.
5. LEP collaboration, CERN-PPE/94–187, November 1994.