37 CFR § 1.501 - Citation of prior art and written statements in patent files.
(a) Information content of submission: At any time during the period of enforceability of a patent, any person may file a written submission with the Office under this section, which is directed to the following information:
(1) Prior art consisting of patents or printed publications which the person making the submission believes to have a bearing on the patentability of any claim of the patent; or
(2) Statements of the patent owner filed by the patent owner in a proceeding before a Federal court or the Office in which the patent owner took a position on the scope of any claim of the patent. Any statement submitted under this paragraph must be accompanied by any other documents, pleadings, or evidence from the proceeding in which the statement was filed that address the written statement, and such statement and accompanying information under this paragraph must be submitted in redacted form to exclude information subject to an applicable protective order.
(3) Submissions under paragraph (a)(2) of this section must identify:
(i) The forum and proceeding in which patent owner filed each statement;
(ii) The specific papers and portions of the papers submitted that contain the statements; and
(iii) How each statement submitted is a statement in which patent owner took a position on the scope of any claim in the patent.
(b) Explanation: A submission pursuant to paragraph (a) of this section:
(1) Must include an explanation in writing of the pertinence and manner of applying any prior art submitted under paragraph (a)(1) of this section and any written statement and accompanying information submitted under paragraph (a)(2) of this section to at least one claim of the patent, in order for the submission to become a part of the official file of the patent; and
(2) May, if the submission is made by the patent owner, include an explanation of how the claims differ from any prior art submitted under paragraph (a)(1) of this section or any written statements and accompanying information submitted under paragraph (a)(2) of this section.
(c) Reexamination pending: If a reexamination proceeding has been requested and is pending for the patent in which the submission is filed, entry of the submission into the official file of the patent is subject to the provisions of §§ 1.502 and 1.902.
(d) Identity: If the person making the submission wishes his or her identity to be excluded from the patent file and kept confidential, the submission papers must be submitted anonymously without any identification of the person making the submission.
(e) Certificate of Service: A submission under this section by a person other than the patent owner must include a certification that a copy of the submission was served in its entirety upon patent owner at the address as provided for in § 1.33 (c). A submission by a person other than the patent owner that fails to include proper proof of service as required by § 1.248(b) will not be entered into the patent file.