(a) In this section, "net revenue" means the authority's gross revenue less the amount necessary to pay the cost of maintaining and operating the authority and the authority's property.
(b) Authority bonds may be secured by a pledge of:
(1) all or part of the authority's net revenue;
(2) the net revenue of a contract entered into at any time; or
(3) other revenue specified by board resolution.
(c) The pledge may reserve the right to issue additional bonds on a parity with or subordinate to the bonds being issued, subject to conditions specified by the pledge.