Neb. Rev. Stat. § 23-127: Neb. Rev. Stat. § 23-127

When the question submitted involves the borrowing or expenditure of money, or issuance of bonds, the proposition of the question must be accompanied by a provision to levy a tax annually for the payment of interest, if any thereon, and no vote adopting the question proposed shall be valid unless it likewise adopt the amount of tax to be levied to meet the liability incurred.