Okla. Stat. tit. 73, § 175

The Oklahoma Capitol Improvement Authority is hereby authorized and directed to construct, from funds legally available, a system of tunnels to connect the Will Rogers Building to the Tax Commission Building, the Tax Commission Building to the Education Building, the Education Building to the Sequoyah Building, the Capitol Building to the parking lot to the southeast of said Capitol Building east of Lincoln Boulevard, and the Sequoyah Building-Education Building tunnel to the parking lot east of the Sequoyah Building located east of Lincoln Boulevard.