Revenue bonds issued under this subtitle shall be executed on behalf of the Authority by the manual signature of at least one authorized individual. Other signatures on the bonds may be either manual or facsimile. If an individual whose manual or facsimile signature appears on any bond or coupon issued under this subtitle ceases to serve in an authorized capacity before the delivery of the bond, the signature nevertheless is as valid and sufficient for all purposes as if the individual had remained in that capacity until delivery of the bond.