Washington Revised Code Title 11. Probate and Trust Law § 11.20.090. Admission to probate of foreign will

Wills probated in any other state or territory of the United States, or in any foreign country or state, shall be admitted to probate in this state on the production of a copy of such will and of the original record of probate thereof, certified by the attestation of the clerk of the court in which such probation was made; or if there be no clerk, certification by the attestation of the judge thereof, and by the seal of such officers, if they have a seal.