Upon the result of such question being certified by the election authority respectively to the board and if the proposition to incur or increase such indebtedness be assented to by voters voting on the question as required by or hereafter may be required by § 26(b) of Article VI of the Missouri Constitution, the board may by resolution declare the results of the submission of the question and cause the bonds of such district to be issued, payable to the bearer, not exceeding the amount authorized, and in denominations of not less than one hundred dollars, or some multiple thereof, payable in not more than twenty years from the date they bear with interest from the date at a rate not exceeding the highest rate of interest permitted by law payable semiannually which bonds shall have interest coupons attached to conform to the fact thereof. All such bonds shall be signed by the chairman of the board, attested by the signature of the secretary, and each bond shall have impressed thereon the corporate seal of the district, that whenever one thousand or more bonds are to be executed as of the same date, the resolution pursuant to which such bonds are issued may direct that such bonds be executed by the facsimile signature of the chairman and secretary of the board. Such bonds may be negotiated and sold but in no case shall they be sold for less than par.