Neb. Rev. Stat. §§ 85-1523
The proceeds of revenue bonds provided for in section 85-1515, 85-1520, or 85-1521 shall be used solely for the purpose for which the bonds are issued and for the expenses of issuing such bonds. The board shall establish and maintain a schedule of rates, fees, or charges for the use of the facilities constructed or acquired by the issuance of revenue bonds and other facilities controlled by the board, the revenue of which, in whole or in part, is pledged to the holder of the bonds, which shall be in an amount at least sufficient, on the amortization plan, to pay the operating and maintenance charges of the facilities and the principal and interest representing the indebtedness against the income and revenue therefrom.
Neb. Rev. Stat. §§ 85-1523