Wis. Stat. § 67.06
Every municipal bond shall be a negotiable instrument payable to bearer, or, in case of registered bonds, to the registered owner; shall bear interest; shall specify the times and the place or places of payment of principal and interest; shall be numbered consecutively with the other bonds of the same issue which shall begin with number one and continue upward, or, if so directed by the governing body, shall begin with any other number and continue upward; shall bear on its face a name indicative of the purpose specified for it in the resolution of the governing body authorizing its issuance or in a resolution pursuant to s. 67.05(13); shall contain a statement that a direct annual irrepealable tax has been levied by the municipality sufficient to pay the interest when it falls due, and also to pay and discharge the principal at maturity; may contain a statement that the bond is callable with or without premium on conditions prescribed on it; and may contain any other statement of fact not in conflict with the resolution. The entire issue may be composed of bonds of a single denomination or 2 or more denominations.
Wis. Stat. § 67.06