Okla. Stat. tit. 58, § 58-550: Vouchers or other proof of payment to accompany account

In rendering his account, the executor or administrator must,

upon request of the court or an interested party, file vouchers or

other proof of payment for all charges, debts, claims, and expenses

which he has paid, which must remain in the court; and he may be

examined on oath touching such payments, and also touching any

property and effects of the decedent, and the disposition thereof.

When any voucher or other proof of payment is required for other

purposes, it may be withdrawn on leaving a certified copy on file;

if a voucher or other proof of payment is lost, or for other good

reason cannot be produced on the settlement, the payment may be

proved by the oath of any competent witness.

R.L. 1910, § 6437. Amended by Laws 1994, c. 234, § 2, eff. Sept. 1,

1994.