O.C.G.A. § 46-3-135 (2019)

(a) All or any part of the gross or net revenues and earnings derived from any particular project and any and all revenues and earnings received by the authority, regardless of whether such revenues and earnings were produced by a particular project for which bonds have been issued, may be pledged by the authority to the payment of the principal of and interest on revenue bonds of the authority as may be provided in any resolution authorizing the issuance of such bonds or in any trust instrument pertaining to such bonds.

(b) Such funds so pledged, from whatever source received, may include funds received from one or more or all sources and may be set aside at regular intervals into sinking funds for which provision may be made in any such resolution or trust instrument, which sinking funds may be pledged to and charged with the payment of:

(1) The interest upon such revenue bonds as such interest shall become due;

(2) The principal of the bonds as the same shall mature;

(3) The necessary charges of any trustee, paying agent, or registrar for such bonds; and

(4) Any premium upon bonds retired upon call or purchase.

(c) The use and disposition of any sinking fund may be subject to regulations for which provision may be made in the resolution authorizing the issuance of the bonds or in the trust instrument or indenture securing the payment of the same.