Neb. Rev. Stat. § 49-216: Neb. Rev. Stat. § 49-216

Five of the signers to each separate petition shall swear before a notary public, or other officer entitled to administer oaths, that the petition is bona fide in every respect to the best of their knowledge and belief, and such oath shall be annexed to the petition. If the petition contains less than five signers, the oath shall be signed by all the signers.