The Notes shall be signed on behalf of the Board by the chairman or vice-chairman of the Board, or shall bear the facsimile signature of such officer, and shall bear the official seal of the Board, which shall be attested by the manual or facsimile signature of the secretary or assistant secretary of the Board. In the event that Notes shall bear the facsimile signature of the chairman or vice-chairman of the Board, such Notes shall be signed by such administrative assistant as the chairman of the Board shall determine or by any registrar/paying agent that may be designated by the Board. In case any officer whose signature or a facsimile of whose signature appears on any Notes shall cease to be such officer before the delivery of such Notes, such signature or facsimile signature nevertheless shall be valid and sufficient for all purposes as if such officer had remained in office until such delivery.