(a) In this section, 'net revenue' means the gross revenue of the district less the amount necessary to pay the cost of maintaining and operating the district and its property.(b) Bonds issued under this subchapter may be secured under board resolution by a pledge of:(1) all or part of the district's net revenue;(2) the net revenue of one or more contracts made before or after the issuance of the bonds; 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.(d) Bonds not payable wholly or partly from ad valorem taxes may be issued without an election. Added by Acts 2007, 80th Leg., R.S., Ch. 920 (H.B. 3166), Sec. 1.06, eff. April 1, 2009.