Okla. Stat. tit. 58, § 58-334: Signing of claim - Contents of claim - Proof of claim

Every claim shall be signed by the claimant or the claimant's

authorized representative. Every claim which is due when presented

to the personal representative shall state the exact amount claimed

and shall state with reasonable particularity the nature and source

of the claim, and if the claim is secured by a security interest,

mortgage or other lien which has been filed or recorded according to

law, a brief description of such interest, mortgage or lien and of

the collateral covered thereby shall be stated in the claim. If the

claim be not due when presented, or be contingent, the particulars

of such claim must be stated. The personal representative may

require satisfactory vouchers or proofs or other evidence to be

produced in support of the claim. If the estate is insolvent, no

greater rate of interest shall be allowed upon any claim, after the

first publication of notice to creditors, than is allowed by law on

judgments obtained in the district court.