In case any of the members or officers of the authority whose signatures appear on any bonds or coupons shall cease to be such members or officers before the delivery of such bonds, such signatures shall, nevertheless, be valid and sufficient for all purposes, the same as if such members or officers had remained in office until such delivery. Any provision of any law to the contrary notwithstanding, any bonds issued pursuant to the provisions of section 18-2124 shall be fully negotiable.