1 CFR § 51.7 - What publications are eligible?
(a) A publication is eligible for incorporation by reference under 5 U.S.C. 552(a) if it -
(1) Conforms to the policy stated in § 51.1;
(i) Is published data, criteria, standards, specifications, techniques, illustrations, or similar material; and
(ii) Does not detract from the usefulness of the Federal Register publication system; and
(3) Is reasonably available to and usable by the class of persons affected. In determining whether a publication is usable, the Director will consider -
(i) The completeness and ease of handling of the publication; and
(ii) Whether it is bound, numbered, and organized, as applicable.
(b) The Director will assume that a publication produced by the same agency that is seeking its approval is inappropriate for incorporation by reference. A publication produced by the agency may be approved, if, in the judgment of the Director, it meets the requirements of paragraph (a) and possesses other unique or highly unusual qualities. A publication may be approved if it cannot be printed using the Federal Register/Code of Federal Regulations printing system.
(c) The following materials are not appropriate for incorporation by reference:
(1) Material published previously in the Federal Register.
(2) Material published in the United States Code.