The Clar formulas of a benzenoid system and the resonance graph

It is shown that the number of Clar formulas of a Kekuléan benzenoid system BB is equal to the number of subgraphs of the resonance graph of BB isomorphic to the Cl(B)Cl(B)-dimensional hypercube, where Cl(B)Cl(B) is the Clar number of BB.