Neb. Rev. Stat. § 64-105.02

(1) A notary public may certify the affixation of a signature by mark on a document presented for notarization if: (a) The mark is affixed in the presence of the notary public and of two witnesses unaffected by the document; (b) Both witnesses sign their own names beside the mark; (c) The notary public writes below the mark: "Mark affixed by (name of signer by mark) in presence of (names and addresses of witnesses) and undersigned notary public"; and (d) The notary public notarizes the signature by mark through an acknowledgment, jurat, or signature witnessing. (2) A notary public may sign the name of a person physically unable to sign or make a mark on a document presented for notarization if: (a) The person directs the notary public to do so in the presence of two witnesses unaffected by the document; (b) The notary public signs the person's name in the presence of the person and the witnesses; (c) Both witnesses sign their own names beside the signature; (d) The notary public writes below the signature: "Signature affixed by notary public in the presence of (names and addresses of person and two witnesses)"; and (e) The notary public notarizes the signature through an acknowledgment, jurat, or signature witnessing.