“ All official military, naval, or air-force books, pamphlets, documents, reports, maps, charts, plans, designs, models, drawings, photographs, contracts, or specifications which are now marked under the authority or at the direction of the President, the Secretary of Defense, the Secretary of the Army, the Secretary of the Navy, or the Secretary of the Air Force as “top secret”, “secret”, “confidential”, or “restricted” and all such articles or equipment which may hereafter be so marked with the approval or at the direction of the President. ”