Non-patent literature

The EPO's search documentation includes patent literature and any other printed or non-printed matter that may be technically relevant for the patent-granting procedure.

Non-patent literature is assigned NPL reference numbers. These have a format similar to patent publication numbers but, instead of a country code, the letters XP are used.

Examples: XP000000001, XP000123456

It is not currently possible to search for XP documents in the European Patent Register. If you go to Espacenet, you can retrieve XP documents by entering the XP number in the number search, the publication number field of the advanced search mask or in the Smart search mask.