Principles of International Commercial Contracts, 1994 - UNIDROIT
Chapter 3 - Validity
Article 3.11 - Third Persons
(1) Where fraud, threat, gross disparity or a party?s mistake is imputable to, or is known or ought to be known by, a third person for whose acts the other party is responsible, the contract may be avoided under the same conditions as if the behaviour or knowledge had been that of the party itself.
(2) Where fraud, threat or gross disparity is imputable to a third person for whose acts the other party is not responsible, the contract may be avoided if that party knew or ought to have known of the fraud, threat or disparity, or has not at the time of avoidance acted in reliance on the contract.