Okla. Stat. tit. 15, § 15-135: Writing prevented by fraud - Enforcement against

fraudulent party.

Where a contract, which is required by law to be in writing, is

prevented from being put into writing by the fraud of a party

thereto, any other party who is by such fraud led to believe that it

is in writing, and acts upon such belief to his prejudice, may

enforce it against the fraudulent party.