An arbitration clause contained in the articles of association of a sports federation, when incorporated by reference in a contract between sports companies having as its subject matter economic and financial relationships, is ineffective where it lacks a specific definition of its scope, identified in abstract and generic terms, as it is not apt to derogate from the jurisdiction of the ordinary courts within the meaning of Article 3(1) of Decree-Law No. 220/2003, converted with amendments by Law No. 280/2003.