Nebraska Revised Statute 32-1407
(1) Initiative petitions shall be filed in the office of the Secretary of State at least four months prior to the general election at which the proposal would be submitted to the voters.
(2) When a copy of the form of any initiative petition is filed with the Secretary of State prior to obtaining signatures, the issue presented by such petition shall be placed before the voters at the next general election occurring at least four months after the date that such copy is filed if the signed petitions are found to be valid and sufficient. All signed initiative petitions shall become invalid on the date of the first general election occurring at least four months after the date on which the copy of the form is filed with the Secretary of State.
(3) Petitions invoking a referendum shall be filed in the office of the Secretary of State within ninety days after the Legislature at which the act sought to be referred was passed has adjourned sine die or has adjourned for more than ninety days.
Laws 1994, LB 76, § 389.