The agreements will always be signed by the rectors of each university (or persons delegated for the purpose) and by the doctoral student. They may also be signed by other persons involved (thesis supervisors, persons responsible for the doctoral programs, directors of the doctoral schools, etc.).
The UPV/EHU proposes the signing of the agreement in a single document, drawn up in the official languages of the signatory universities. It will normally be a trilingual document with three columns, but it may be drawn up in as many as four languages.