The easiest way to retrieve a patent document from a patent database is by its publication or patent number. Patent documents can be identified by one or more numbers, including:
The patent number usually appears in the top right-hand corner of the front page of a patent document.
Patent document numbers consist of three parts: a country code that identifies the country of origin, a document number and a kind code that identifies the type of document. Common country codes include CA (Canada), DE (Germany), EP (European Patent Office), JP (Japan) and US (United States). Kind codes include A (published application), B (US patent) and C (CA patent).