  The most recent results from the B-factories on the time-dependent CP
asymmetries measured in B0-decays mediated by b --> c c(bar) s
quark-transitions are reviewed. The Standard Model interpretation of the
results in terms of the parameter sin2beta leads to a four-fold ambiguity on
the unitarity triangle beta which can be reduced to a two-fold ambiguity by
measuring the sign of the parameter cos2beta. The results on cos2beta obtained
so far are reviewed.
