Pub. L. 101-163, tit. III, sec. 310

Sec. 310. There is established, as a joint office of Congress, the Special Services Office, which (under the supervision and control of a board, to be known as the Special Services Board, comprised of the Clerk of the House of Representatives, the Sergeant at Arms and Doorkeeper of the Senate, and the Librarian of Congress) shall provide special services to Members of Congress, and to officers, employees, and guests of Congress.