Revisiting B → Dlv

We reexamine the determination of vertical bar V-cb vertical bar from B -> Dlv. in view of recent experimental and theoretical progress, discussing the parameterization of the form factors and studying the role played by the unitarity constraints. Our fit to experimental and lattice results forB -> Dlv. gives vertical bar V-cb vertical bar = 40.49(97)10(-3) and to R(D) = 0.299(3).