Okla. Stat. tit. 40, § 2-703
"Extended benefit period" means a period which shall:
(2) end with either of the following weeks, whichever occurs later:
(b) the thirteenth consecutive week of such period.
No extended benefit period may begin by reason of a state "on" indicator before the fourteenth week following the end of a prior extended benefit period which was in effect with respect to this state.
Laws 1980, SB 637, c. 323, § 2-703, emerg. eff. July 1, 1980; Amended by Laws 1982, HB 1808, c. 304, § 11, eff. October 1, 1982.