Ga. Code § 50-9-42
The revenues, rents, and earnings derived from any particular project or combined project or any and all funds from any source received by any department, board, commission, or agency of the state and pledged and allocated by it to the authority as security for the performance of any lease or leases or any and all revenues, rents, and earnings received by the authority, regardless of whether or not such rents, earnings, and revenues were produced by a particular project for which bonds have been issued unless otherwise pledged and allocated, may be pledged and allocated by the authority to the payment of the principal and interest on revenue bonds of the authority as the resolution authorizing the issuance of the bonds or in the trust instrument may provide; and such funds so pledged from whatever source received, which pledge may include funds received from one or more or all sources, shall be set aside at regular intervals as may be provided in the resolution or trust indenture into a sinking fund, which sinking fund shall be pledged to and charged with the payment of:
The use and disposition of the sinking fund shall be subject to such regulations as may be provided in the resolution authorizing the issuance of the revenue bonds or in the trust indenture, but, except as may otherwise be provided in the resolution or trust indenture, such sinking fund shall be a fund for the benefit of all revenue bonds without distinction or priority of one over another. Subject to the resolution authorizing the issuance of the bonds or in the trust indenture, surplus moneys in the sinking fund may be applied to the purchasing or redemption of bonds; and any such bonds so purchased or redeemed shall immediately be canceled and shall not again be issued.
OCGA § 50-9-42