Any notices, requests, demands and other communications provided for by this Agreement shall be sufficient if in writing and delivered in person or sent by a nationally recognized overnight courier service or by registered or certified mail, postage prepaid, return receipt requested, to the Executive at the last address the Executive has filed in writing with the Employer or, in the case of the Employer, at its main offices, attention of the Chief Executive Officer, and shall be effective on the date of delivery in person or by courier or three (3) days after the date mailed.