All notices, demands, instructions and other communications required or permitted under this Agreement must be in writing and will be deemed to have been duly given upon delivery or, in the case of a letter mailed by registered first class mail, postage prepaid, three days after deposit in the mail. Unless otherwise specified in a notice sent in accordance with the provisions of this Section 23 , notices, demands, instructions and other communications in writing will be given to the respective parties at their respective addresses listed on the signature page to this Agreement.