Okla. Stat. tit. 16, § 16-37: Foreign acknowledgments legalized

All deeds, mortgages, oil and gas leases, powers of attorney and

other instruments of writing for the conveyance or encumbrance of

any lands, tenements, or hereditaments situated within this state,

heretofore executed and acknowledged or proved in any state,

territory, District of Columbia or country in conformity with the

law of such state, territory, District of Columbia or country, shall

be as valid as if executed within this state in conformity with the

provisions of the laws of this state. Provided this act shall not

validate any acknowledgemts fraudulently obtained.