Okla. Stat. tit. 70, § 70-4008: Form of bonds - Approval by Attorney General

All bonds issued hereunder shall have on the backs thereof the

certificate required by Section 29 of Article X of the Constitution

of Oklahoma. Such bonds and any bonds or other obligations issued

under the Oklahoma Higher Education Promise of Excellence Act of

2005 shall be submitted to the Attorney General of Oklahoma for

examination; and such bonds, when having been examined and certified

as legal obligations by the Attorney General in accordance with such

requirements as he or she may make, shall be incontestable in any

court in the State of Oklahoma unless suit thereon shall be brought

in a court having jurisdiction thereof within thirty (30) days from

the date of such approval. Bonds so approved by the Attorney

General shall be prima facie valid and binding obligations according

to their terms, and the only defense which may be offered thereto in

any suit instituted after such thirty-day period shall have expired

shall be forgery, fraud or violation of the Constitution.