Artikel 18

If the parties agree to submit the disputes mentioned in the preceding article to an arbitral tribunal, they shall draw up a special agreement in which they shall specify the subject of the dispute, the arbitrators selected, and the procedure to be followed. In the absence of sufficient particulars in the special agreement, the provisions of the Hague Convention of 18 October 1907 for the Pacific Settlement of International Disputes shall apply so far as is necessary.
If nothing is laid down in the special agreement as to the rules regarding the substance of the dispute to be followed by the arbitrators, the Tribunal shall apply the substantive rules enumerated in Article 38 of the Statute of the International Court of Justice.