There is an agreement in writing—
Where parties agree otherwise than in writing by reference to terms which are in writing, they make an agreement in writing.
An agreement is evidenced in writing if an agreement made otherwise than in writing is recorded by one of the parties, or by a third party, with the authority of the parties to the agreement.
An exchange of written submissions in arbitral or legal proceedings in which the existence of an agreement otherwise than in writing is alleged by one party against another party and not denied by the other party in his response constitutes as between those parties an agreement in writing to the effect alleged.
References in this Part to anything being written or in writing include its being recorded by any means.