  We discuss the role of nonclassicality of quantum states as a necessary
resource in deterministic generation of multipartite entangled states. In
particular for three bilinearly coupled modes of the electromagnetic field,
tuning of the coupling constants between the parties allows the total system to
evolve into both Bell and GHZ states only when one of the parties is initially
prepared in a nonclassical state. A superposition resource is then converted
into an entanglement resource.
