38 C.F.R. § 10.20
Certification to the execution of demand for payment forms appearing on the reverse side of adjusted service certificates issued pursuant to the World War Adjusted Compensation Act, as amended, is required in accordance with instructions printed on said forms. Such certification if made in the United States or possessions will be accepted if made by and bearing the official seal of a United States postmaster, an executive officer of an incorporated bank or trust company, notary public, or any person who is legally authorized to administer oaths in a State, Territory, District of Columbia or in a Federal judicial district of the United States. If the demand for payment be executed in a foreign country, the same shall be certified by an American consul, a recognized representative of an American embassy or legation or by a person authorized to administer oaths under the laws of the place where execution of demand is made, provided there be attached to the certificate of such latter officer a proper certification by an accredited official of the State Department of the United States that the officer certifying to the execution of the demand for payment was authorized to administer oaths in the place where certification was made.
38 C.F.R. §10.20