32 CFR §516.26

1. (a)General. Under the provisions of 28 U.S.C. l746, whenever any matter is required or permitted to be established or proven by a sworn statement, oath or affidavit, such matter may also be established or proven by an unsworn written declaration under penalty of perjury. Because such declaration does not require a notary or other official to administer oaths, individuals preparing statements for use in litigation should consider using this format. (See figure C-3, appendix G, of this part).
2. (b)When executed within the United States. Place the following at the end of the witness statement:
3. (c)When executed outside the United States. Place the following at the end of the witness statement: