1. L. B. Okun, Leptons and Quarks (North-Holland Publishing Company, Amsterdam, 1982 )
2. H. Fritzsch and P. Minkowski, Phys. Rep. 73 (1981) 67.
3. Particle Data Group, Rev. Mod. Phys. 56 (1984) 1.
4. R. Rückl, Weak Decays of Heavy Flavours, CERN preprint, 1983.
5. See, for example, L.-L. Chau, Phys. Rep. I5C (1983) 1 and these Proceedings.