Neb. Rev. Stat. § 18-2464

An agency may issue such types of bonds as its board may determine, subject only to any agreement with the holders of outstanding bonds, including bonds as to which the principal and interest are payable exclusively from all or a portion of the revenue from one or more projects, or from one or more revenue-producing contracts made by the agency with any person, or from its revenue generally, or which may be additionally secured by a pledge of any grant, subsidy, or contribution from any person, or a pledge of any income or revenue, funds, or money of the agency from any source whatsoever or a mortgage or security interest in any real or personal property, commodity, product, or service or interest therein.