(a) Bonds are payable solely from and shall be secured by a pledge of:
(1) revenues of the issuer derived from the lease or sale of a system;
(2) amounts attributable to bond proceeds; or
(3) amounts obtained through the exercise of a remedy provided by the governing body's resolution or a security agreement securing the bonds in the manner specified in the resolution or security agreement.
(b) The governing body shall fix and periodically revise payments under a lease or contract for sale of a system so that the payments and other pledged revenue will be sufficient to pay the bonds and interest on the bonds as they mature and become due and to maintain reserve or other funds as provided by the resolution or security agreement.
(c) The governing body may direct the investment of money in the funds created by the resolution or security agreement, and may delegate this authority to its authorized agent.