Documents relating to more than one application or patent (e.g. an individual or a general authorisation), or having to be communicated to more than one party, only need to be filed in one copy (see also A‑VIII, 1.5). However, letters accompanying submitted documents (in particular EPO Form 1038) must be filed in one copy for each file to which the document they accompany relates.

For example, where two different applications share a common priority claim, the applicant only needs to file one copy of the priority document, but this must be accompanied by two different letters each relating to one or the other application (preferably two copies of Form 1038). Each letter (or EPO Form 1038) must be duly signed and indicate one or the other of the two application numbers in respect of which the priority document is being filed (see also A‑VIII, 3.1).