Exclusive and inclusive decays ofBmesons intoDsmesons

We have studied the production of ${\mathit{D}}_{\mathit{s}}$ mesons in the decays of B mesons at the \ensuremath{\Upsilon}(4S) resonance. We report on the first observation of exclusive B-meson decays B-g${\mathit{D}}_{\mathit{s}}^{\mathrm{\ensuremath{-}}}$${\mathit{D}}^{\mathrm{*}+}$, B\ensuremath{\rightarrow}${\mathit{D}}_{\mathit{s}}^{\mathrm{\ensuremath{-}}}$${\mathit{D}}^{+}$, and B\ensuremath{\rightarrow}${\mathit{D}}_{\mathit{s}}^{\mathrm{\ensuremath{-}}}$${\mathit{D}}^{0}$. We also present a new measurement of the branching ratio and the momentum spectrum for the inclusive decay B\ensuremath{\rightarrow}${\mathit{D}}_{\mathit{s}}$X.