Oregon Revised Statutes Public Borrowing § 289.215

The validity of bonds issued under this chapter is not dependent on or affected by the validity or regularity of any proceeding relating to the acquisition, purchase, construction, reconstruction, installation, improvement, betterment, extension, management, operation or funding of the project for which the bonds are issued. The official action authorizing such bonds may provide that the bonds shall contain a recital that they are issued pursuant to this chapter and such recital shall be conclusive evidence of their validity and of the regularity of their issuance.