Neb. Rev. Stat. §§ 18-2525
Whenever an initiative petition bearing signatures equal in number to at least twenty percent of the qualified electors of a municipality, which petition requests that a special election be called to submit the initiative measure to a vote of the people, has been filed with the city clerk and verified pursuant to section 18-2518, it shall be the duty of the governing body of such municipality to consider passage of the measure contained in the petition, including an override of any veto, if necessary. If the governing body fails to pass the measure, without amendment, including an override of any veto, if necessary, within thirty days from the date it received notification pursuant to section 18-2518, the city clerk shall cause the measure to be submitted to a vote of the people at a special election called for such purpose. Subject to the provisions of section 18-2521, the date of such election shall be set during the first available month that complies with sections 32-405 and 32-559.
Neb. Rev. Stat. §§ 18-2525