The said period may be extended if compelling circumstances prevent from making this appointment in due time.
3. The appointing authority shall, at the request of one of the parties, appoint the sole arbitrator as promptly as possible. In making the appointment the appointing authority shall use the following list-procedure, unless both parties agree that the list-procedure should not be used or unless the appointing authority determines in its discretion that the use of the list-procedure is not appropriate for the case:
a)  At the request of one of the parties the appointing authority shall communicate to both parties an identical list containing at least three names;
b) Within fifteen days after the receipt of the list, each party may return the list to the appointing authority after having deleted the name or names to which he objects and numbered the remaining names on the list in the order of his preference;
c) After the expiration of the above period of time, the appointing authority shall appoint the sole arbitrator from among the names approved on the lists returned to it and in accordance with the order of preference indicated by the parties;
d) If for any reason the appointment cannot be made according to the procedure, the appointing authority may exercise its discretion in appointing the sole arbitrator.
4.  In making the appointment, the appointing authority shall have regard to such considerations as are likely to secure the appointment of an independent and impartial arbitrator and shall take into account as well the advisability of appointing an arbitrator of a nationality other than the nationalities of the parties.

Article 7
1. If three arbitrators are to be appointed, each party shall appoint one arbitrator. The two arbitrators thus appointed should choose the third arbitrator who will act as the presiding arbitrator of the tribunal.