Determine which legal clause the following paragraph belongs to: 13.5 The Supplier shall ensure that any Associated Parties and sub- contractors who are performing services in connection with this Agreement do so only on the basis of a written contract which imposes on and secures from such person terms equivalent to those imposed on the Supplier in this clause( " Relevant Terms" ) . The Supplier shall be responsible for the observance and performance by such persons of the Relevant Terms and shall be directly liable to the Client for any breach of such persons of any of the Relevant Terms.