An arbitration clause contained in a preliminary contract does not automatically extend to a subsequent preliminary contract entered into between the same parties, where the latter presupposes the termination of the former and governs the contractual obligations differently, even if its recitals refer to the previous instruments as forming an integral part thereof, in the absence of an express reproduction of, or an unequivocal reference to, the intention to maintain the arbitration agreement, to be construed in accordance with the real common intention of the parties pursuant to Article 1362 of the Civil Code.