Okla. Stat. tit. 84, § 84-261: Proof of service

Service by publication in such cases shall be deemed complete

when it shall have been made in the manner and for the times

prescribed in this section. Proof of the publication of the notice

shall be made by the affidavit of the printer, or his foreman, or

principal clerk, or other person knowing the same, and proof of

mailing the said copy, or that the place of residence of such

defendants or any of them is unknown to the plaintiff, shall be

entered by the affidavit of the plaintiff, his agent or attorney.

But no judgment by default shall be entered against the defendants

so described on such service until proof thereof be made, and

approved by the court and filed.