espacenetEspacenet officially covers European (EPO) and World (WIPO) patents but includes current US and Japan patents. Full searching for the current 24 months. Free (page-by-page) retrieval of individual patents by number (PDF format) varies by country; some begin with 1920. Special note: these patents have alphanumeric subcodes, such as EP 1234567 A3, indicating the presence or lack of supporting documentation.