Okla. Stat. tit. 41, § 41-2: Tenant holding over as tenant at will - Expiration of

unwritten contract.

When premises are let for one or more years, and the tenant,

with the assent of the landlord, continues to occupy the premises

after the expiration of the term, such tenant shall be deemed to be

a tenant at will; provided, that no lease or rental contract of

premises shall be continued, unless the original contract was in

writing, and all other lease or contracts shall expire by limitation

with the calendar year, without notice.