CFR > Title 37 - Patents, Trademarks, and Copyrights > CHAPTER I—UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE > SUBCHAPTER A—GENERAL (parts 1 to 5) > PART 1—RULES OF PRACTICE IN PATENT CASES > SUBPART D—Ex Parte Reexamination of Patents (§1.501 to §1.570) > 1.501—Citation of prior art in patent files.

1.501—Citation of prior art in patent files.

(a) At any time during the period of enforceability of a patent, any person may cite, to the Office in writing, prior art consisting of patents or printed publications which that person states to be pertinent and applicable to the patent and believes to have a bearing on the patentability of any claim of the patent. If the citation is made by the patent owner, the explanation of pertinency and applicability may include an explanation of how the claims differ from the prior art. Such citations shall be entered in the patent file except as set forth in §§ 1.502 and 1.902.
(b) If the person making the citation wishes his or her identity to be excluded from the patent file and kept confidential, the citation papers must be submitted without any identification of the person making the submission.
(c) Citation of patents or printed publications by the public in patent files should either:
(1) Reflect that a copy of the same has been mailed to the patent owner at the address as provided for in § 1.33(c); or in the event service is not possible
(2) Be filed with the Office in duplicate.

Code of Federal Regulations

[46 FR 29185, May 29, 1981, as amended at 65 FR 76774, Dec. 7, 2000]