Branching ratios of $B^+ \to D^{(*)+}K^{(*)0}$ decays in perturbative   QCD approach
  We study the rare decays $B^+ \to D^{(*)+}K^{(*)0}$, which can occur only via annihilation type diagrams in the standard model. We calculate all of the four modes, $B \to PP, VP, PV, VV$, in the framework of perturbative QCD approach and give the branching ratios of the order about $10^{-6}$. 
Ge-Liang Song, Cai-Dian L\"u