All bonds issued pursuant to this article shall be obligations of the board issuing such bonds, payable only in accordance with the terms thereof, and shall not be obligations general, special or otherwise of the state of Arizona. Such bonds shall not constitute a debt, legal or moral, of the state of Arizona, and shall not be enforceable against the state, nor shall payment thereof be enforceable out of any funds of the board or the institution issuing such bonds other than the income and revenue pledged and assigned to, or in trust for the benefit of, the holder or holders of such bonds.