2. If within thirty days after the receipt of a party’s notification of the appointment of an arbitrator, the other party has not notified the first party of the arbitrator he has appointed:
a) The first party may request the appointing authority previously designated by the parties to appoint the second arbitrator; or
b) If no such authority has been previously designated by the parties, or if the appointing authority previously designated refuses to act or fails to appoint the arbitrator within thirty days after the receipt of a party’s request thereof, the first party may request the Director of the Centre to make such appointment. The Centre may make such appointment according to the procedures outlined in article (6/3), or designate the appointing authority. The first party may then request the appointing authority so designated to appoint the second arbitrator. In either case, the appointing authority may exercise its discretion in appointing the arbitrator.
3. If within thirty days after the appointment of the second arbitrator, the two arbitrators have not agreed on the choice of the presiding arbitrator, the presiding arbitrator shall be appointed by an appointing authority in the same way as a sole arbitrator would be appointed under article (6).

Article 8
1. When an appointing authority is requested to appoint an arbitrator pursuant to article (6) or article (7), the party which makes the request shall send to the appointing authority a copy of the notice of arbitration, a copy of the contract out of or in relation to which the dispute has arisen and a copy of the arbitration agreement if it is not contained in the contract. The appointing authority may require from either party such information, as it deems necessary to fulfill its function.