9.2.4 Use of "P" documents in the search report 

Although "P" documents are normally not used for the further examination they should be indicated in the search report since they might become pertinent at a later national stage. The EPO as ISA also cites non-patent literature P‑X documents in the search report. If the priority document is not available to the examiner at the time of the search, it will be assumed that the priority is valid for the purpose of establishing the search report and written opinion. For the relevant dates for conducting the search, see GL/PCT‑EPO B‑VI, 3.

Furthermore, section B‑X, 9.2.4 in the Guidelines for Examination in the EPO applies mutatis mutandis.