Okla. Stat. tit. 70 § 16-111.1
The funds allocated for textbooks in Section 16-114a of this title may be used by a school district for supplementary textbooks and other instructional materials other than those selected and placed on the list of textbooks by the State Textbook Committee. The local textbook committee shall submit a statement to the local board of education justifying any such selections. For purposes of this section, "supplementary textbooks and other instructional materials" shall mean materials pertaining to subjects that are not reviewed by the State Textbook Committee or materials that support instruction in the subject matter standards as adopted by the State Board of Education in Section 11-103.6 of this title that were not reviewed by the State Textbook Committee.
Okla. Stat. tit. 70, § 16-111.1