Bond anticipation notes, revenue bonds, or refunding bonds bearing the manual or facsimile signatures of the appropriate officers who are in office on the date of signing are valid and binding obligations notwithstanding that before the delivery and payment any or all of the individuals whose signatures appear on the notes or bonds have ceased to be officers of the issuing district. The resolution authorizing the notes or bonds may provide that the notes or bonds must contain a recital that they are issued under this chapter and the recital is conclusive evidence of their validity and of the regularity of their issuance.