Okla. Stat. tit. 36 § 3634
Medical or surgical services or procedures constituting the practice of podiatric medicine, as defined by Section 142 of Title 59 of the Oklahoma Statutes, psychological services or procedures constituting the practice of psychology, as defined by Section 1352 of Title 59 of the Oklahoma Statutes, and licensed and certified clinical social work services provided by persons meeting the qualifications required under subsection B of Section 1261.1 of Title 59 of the Oklahoma Statutes and covered by the terms of any individual, group, blanket or franchise policy, agreement or service contract providing accident or health benefits coverage in Oklahoma issued by any insurer, whether a stock or mutual insurance company, a medical service corporation or association, or any other type of issuer whatever, and covering an Oklahoma risk may be performed by any practitioner licensed to do so under Sections 136 through 160.2, Sections 1351 through 1376 or subsection B of Section 1261.1 of Title 59 of the Oklahoma Statutes, who is selected by the insured provided that where covered benefits are offered through a contracting preferred provider organization, the podiatrist, psychologist, or clinical social worker is a contracting provider. Except in the case of a contracting preferred provider organization, any provision, exclusion or limitation in such a policy denying an insured the free choice of such licensed podiatric physician, psychologist or certified clinical social worker shall, to the extent of the denial, be void, but such voidance shall not affect the validity of the other provisions of the policy.
Okla. Stat. tit. 36, § 3634