Exclusive Nonleptonic Decays of Heavy Mesons in QCD
  We use operator product expansion and QCD light-cone sum rules to estimate the amplitude of the decay $B \to J/\psi K $ taking into account leading nonfactorizable contributions. The result is very similar to the estimate obtained earlier from a four-point QCD sum rule. We discuss applications of this method to other nonleptonic $B$ decay modes. 
A. Khodjamirian and R. R\"uckl