Section 99.510 - Commissioner's signature on bonds - validity - bonds deemed to be issued for lawful purpose1. In case any of the commissioners or officers of the authority whose signatures appear on any bonds or coupons shall cease to be such commissioners or officers before the delivery of such bonds, such signatures shall, nevertheless, be valid and sufficient for all purposes, the same as if such commissioners or officers had remained in office until such delivery. Any provision of any law to the contrary notwithstanding, any bonds issued pursuant to sections 99.300 to 99.660 shall be fully negotiable.2. In any suit, action or proceedings involving the validity or enforceability of any bond of an authority or the security therefor, any such bond reciting in substance that it has been issued by the authority to aid in financing a land clearance project, as herein defined, shall be conclusively deemed to have been issued for such purpose and such project shall be conclusively deemed to have been planned, located and carried out in accordance with the purposes and provisions of this law.