MPEP App. AI, Section 507 – Manner of Indicating Certain Special Categories of Documents Cited in the International Search Report

(a) Where any document cited in the international search report refers to an oral disclosure, use, exhibition, or other means referred to in Rule 33.1 (b), the separate indication required by that Rule shall consist of the letter "O" placed next to the citation of the said document.
(b) Where any document cited in the international search report is a published application or patent as defined in Rule 33.1 (c), the special mention required by that Rule shall consist of the letter "E" placed next to the citation of the said document.
(c) Where any document cited in the international search report is not considered to be of particular relevance requiring the use of categories "X" and/or "Y" as provided in Section 505 but defines the general state of the art, it shall be indicated by the letter "A" placed next to the citation of the said document.
(d) Where any document cited in the international search report is a document whose publication date occurred earlier than the international filing date of the international application, but later than the priority date claimed in that application, it shall be indicated by the letter "P" next to the citation of the said document.
(e) Where any document cited in the international search report is a document whose publication date occurred after the filing date or the priority date of the international application and is not in conflict with the said application, but is cited for the principle or theory underlying the invention, which may be useful for a better understanding of the invention, or is cited to show that the reasoning or the facts underlying the invention are incorrect, it shall be indicated by the letter "T" next to the citation of the document.
(f) Where in the international search report any document is cited for reasons other than those referred to in paragraphs (a) to (e), for example:
— a document which may throw doubt on a priority claim,
— a document cited to establish the publication date of another citation,
such document shall be indicated by the letter "L" next to the citation of the document and the reason for citing the document shall be given.
(g) Where a document is a member of a patent family, it shall, whenever feasible, be mentioned in the international search report in addition to the one cited belonging as well to this family and should be preceded by the sign ampersand (&). Members of a patent family may also be mentioned on a separate sheet, provided that the family to which they belong shall be clearly identified and that any text matter on that sheet, if not in the English language, shall also be furnished to the International Bureau in English translation.
(h) A document whose contents have not been verified by the search examiner but are believed to be substantially identical with those of another document which the search examiner has inspected, may be cited in the international search report in the manner indicated for patent family members in the first sentence of paragraph (g).