Okla. Stat. tit. 84, § 84-252: Petition - Contents

In all proceedings under this act to determine the question of

heirship of any deceased person it shall be necessary for an heir of

the decedent, or a record claimant of some interest in the estate of

such decedent to file in the proper district court a verified

petition, setting out the name of the deceased, a description of the

estate of which the decedent died seized, respecting which the

question of heirship is sought to be determined, the names and

addresses of all known heirs and record claimants, and the extent of

the interest claimed by such heir or heirs of record claimant, if

known.