35 U.S. Code § 301 - Citation of prior art and written statements
2011—Pub. L. 112–29 amended section generally. Prior to amendment, text read as follows: “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.”
Pub. L. 112–29, § 6(g)(3), Sept. 16, 2011, 125 Stat. 312, provided that:
Section effective July 1, 1981, and applicable to patents in force as of July 1, 1981, or issued thereafter, see section 8(b) of Pub. L. 96–517, set out as an Effective Date of 1980 Amendment note under section 41 of this title.