8. Cross-references between prior-art documents 

If a document (the "primary" document) refers explicitly to another document (the "secondary" document) as providing more detailed information on certain features, the teaching of the latter is to be regarded as incorporated into the primary document if the document was available to the public on the publication date of the primary document (see T 153/85) (for the state of the art pursuant to Art. 54(3), see G‑IV, 5.1 and F‑III, 8, penultimate paragraph). The relevant date for novelty purposes, however, is always the date of the primary document (see G‑IV, 3).