The terms of reference of any expert must include: a precise description of their task, the period laid down for the submission of their opinion, the names of the parties to the proceedings and particulars of the rights which they may invoke under the provisions of Rule 122(2) to Rule 122(4) (regarding travel and subsistence expenses and fees, see E‑IV, 1.10).[Rule 121(2)(a); Rule 121(2)(d); ]