35 U.S.C. 301 Citation of prior art.

Any person at any time may cite to the Office in writing prior art consisting of patents or printed publications which that person believes to have a bearing on the patentability of any claim of a particular patent. If the person explains in writing the pertinency and manner of applying such prior art to at least one claim of the patent, the citation of such prior art and the explanation thereof will become a part of the official file of the patent. At the written request of the person citing the prior art, his or her identity will be excluded from the patent file and kept confidential.

37 C.F.R. 1.501 Citation of prior art in patent files.

1. (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.
2. (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.
3. (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.

37 C.F.R. 1.902 Processing of prior art citations during an inter partes reexamination proceeding.

Citations by the patent owner in accordance with § 1.933 and by an inter partes reexamination third party requester under § 1.915 or § 1.948 will be entered in the inter partes reexamination file. The entry in the patent file of other citations submitted after the date of an order for reexamination pursuant to § 1.931 by persons other than the patent owner, or the third party requester under either § 1.913 or § 1.948, will be delayed until the inter partes reexamination proceeding has been concluded by the issuance and publication of a reexamination certificate. See § 1.502 for processing of prior art citations in patent and reexamination files during an ex parte reexamination proceeding filed under § 1.510.

Public Law 106-113 did not affect the manner of the public’s citation of prior art under 37 CFR 1.501 in a patent. Likewise, it did not affect the Office’s handling of a 37 CFR 1.501 prior art citation in a patent where no reexamination proceeding is pending for that patent when the citation is filed.

Where an inter partes reexamination proceeding is pending when a prior art citation is filed, the following applies:

If the prior art citation satisfies 37 CFR 1.501 and is submitted prior to an order to reexamine, the cited documents (citations) will be considered in an inter partes reexamination proceeding as a prior art citation would be considered in an ex parte reexamination proceeding. See MPEP § 2206.

If the prior art citation satisfies 37 CFR 1.501 and is submitted after an order to reexamine, the citation will be treated as follows:

1. (A) A patent owner citation will normally be considered if it is submitted in time to do so before the reexamination certificate issues.
2. (B) A third party requester citation will be considered if it is submitted as part of a third party requester comments submission under 37 CFR 1.947 or 1.951 (b) (made as required by 37 CFR 1.948 ), or in a properly filed request for reexamination under 37 CFR 1.915 or 1.510.
3. (C) Any other prior art citation satisfying 37 CFR 1.501 which is submitted after an order to reexamine will be retained (stored) in the Central Reexamination Unit or Technology Center (in which the reexamination proceeding is being examined) until the reexamination is concluded by the issuance and publication of a reexamination certificate, after which it will be placed in the file of the patent. 37 CFR 1.902.

See MPEP §§ 2202 through 2206 and 2208 for the manner of making such citations and Office handling of same.