Except as the parties may otherwise agree, any notice, request, bill, or other communication relating to this Agreement, or the rights, obligations or performance of the parties hereunder, shall be in writing and shall be considered as duly delivered when delivered in person or mailed by registered or certified mail, postage prepaid, to the respective post office address of the other parties shown following the signatures of such other parties hereto, or such other address as may be designated by written notice given as provided in this paragraph D.