Neb. Rev. Stat. §§ 43-1409
The signing of a notarized acknowledgment, whether under section 43-1408.01 or otherwise, by the alleged father shall create a rebuttable presumption of paternity as against the alleged father. The signed, notarized acknowledgment is subject to the right of any signatory to rescind the acknowledgment within the earlier of (1) sixty days or (2) the date of an administrative or judicial proceeding relating to the child, including a proceeding to establish a support order in which the signatory is a party. After the rescission period a signed, notarized acknowledgment is considered a legal finding which may be challenged only on the basis of fraud, duress, or material mistake of fact with the burden of proof upon the challenger, and the legal responsibilities, including the child support obligation, of any signatory arising from the acknowledgment shall not be suspended during the challenge, except for good cause shown. Such a signed and notarized acknowledgment or a certified copy or certified reproduction thereof shall be admissible in evidence in any proceeding to establish support.
Neb. Rev. Stat. §§ 43-1409