The bonds shall be payable solely from the rents, revenues, earnings, and funds described in this paragraph, except that the bonds may, in addition and in the discretion of the authority, be paid in part by the authority from any other source of funds lawfully available to the authority for that purpose. The authority shall not be obligated in any way, however, to make any payments from any such other source of funds.
OCGA § 10-9-50