Okla. Stat. tit. 58, § 58-287: Return of inventory

The inventory must be signed by the appraisers, and the executor

or administrator must take and subscribe an oath, before an officer

authorized to administer oaths, that the inventory contains a true

statement of all the estate of the decedent which has come to his

knowledge and possession, and particularly of all money belonging to

the decedent, and of all just claims of the decedent against the

affiant. The oath must be endorsed upon or annexed to the

inventory.