65 ILCS 5/11-74-9

All bonds issued under this Division 74 have a lien upon the income and revenues delivered by the municipality with respect to the industrial project for which the bonds have been issued, and the governing body may provide in the resolution or resolutions authorizing such bonds for the issuance of additional bonds to be equally and ratably secured by a lien upon such income and revenues or may provide that the lien upon such income and revenues for future bonds is subordinate.