Neb. Rev. Stat. §§ 14-518
The powers granted in section 14-517 shall be subject to the conditions set forth in this section. A petition for the creation of a special assessment sewer district and the issuance of special assessment sewer bonds shall be filed with the city clerk of the city, signed by the owners of sixty percent of the real estate contained in any such special assessment sewer district. At the time of the filing of such petition, the city clerk shall cause to be published in the official newspaper of such city for not less than three consecutive days the plan of assessment and amounts proposed to be assessed against each parcel of real estate in such proposed district. Any person signing such petition shall have the absolute right within ten days after such petition shall have been filed with the city clerk to withdraw such person's name from such petition, and in such event such person's name shall not be counted in computing the sixty percent.
Neb. Rev. Stat. §§ 14-518