The testimony of a subscribing witness is not necessary to authenticate a writing unless required by the laws of the jurisdiction whose laws govern the validity of the writing.
Minn. R. Evid. 903
Committee Comment-1977
To authenticate a writing there is no need to present subscribing witnesses unless otherwise required by the laws of the jurisdiction governing the validity of the writing. E.g., Minnesota Statutes 1975 Supplement, section 524.3-406, which in certain circumstances requires the production of an attesting witness.