Revenue bonds issued under this article shall not be deemed to constitute a debt of the state or a pledge of the faith and credit of the state, but such bonds shall be payable solely from the fund provided therefor from earnings and the issuance of such revenue bonds shall not directly or indirectly or contingently obligate the state to levy or to pledge any form of taxation whatever therefor or to make any appropriation for their payment. Neither the state nor the authority shall be obligated to pay the principal of or the interest on such revenue bonds except from earnings of the project or projects for which they shall be issued. All such revenue bonds shall contain recitals on their face covering the foregoing provisions of this Code section.