Such bonds shall be signed on behalf of the board by the chairman of the board and shall be attested by the secretary of the board, one of which signatures may be a facsimile signature, and shall have the seal or facsimile seal of the board impressed or imprinted thereon. All interest coupons attached thereto may be signed with the facsimile signatures of such officials. Such bonds shall be sold in the manner and at such price as the board shall deem advisable, either at public or private sale.
