Article 11: Assembly -- Procedure (1) Each Party shall have one vote in the Assembly. (2) Decisions on matters of substance shall be taken by a two-thirds majority, and on procedural matters by a simple majority, of the Parties present and voting. Parties which abstain from voting shall be considered as not voting. (3) Decisions whether a question is procedural or substantive shall be taken by the Chairman. Such decisions may be overruled by a two-thirds majority of the Parties present and voting. (4) A quorum for any meeting of the Assembly shall consist of a majority of the Parties.