Okla. Stat. tit. 12, § 12-729.7: Assertion of claim or defense using a foreign money

A. A person may assert a claim in a specified foreign money.

If a foreign-money claim is not asserted, the claimant makes the

claim in United States dollars.

B. An opposing party may allege and prove that a claim, in

whole or in part, is in a different money than that asserted by the

claimant.

C. A person may assert a claim as a defense, set-off,

recoupment or counterclaim in any money appropriate for the claim

without regard to the money of other claims.

D. The determination of the proper money of the claim is a

question of law.