Books purporting to be printed or published under the authority of any other state, territory, or foreign country and to contain the statutes, codes, or other written law of such state, territory, or country, or proved to be admitted commonly in the tribunals of such state, territory, or country as evidence of the written law thereof, are admissible in this state as evidence of such law. The unwritten or common law of any other state, territory, or country may be proved as a fact by parol evidence and the books of reports of cases adjudged in the courts of any such state, territory, or country also may be admitted as presumptive evidence of such law.
N.D.C.C. § 31-09-01