Studied in 1959, the Saturn B-1,[1] was a four-stage concept rocket similar to the Jupiter-C, and consisted of a Saturn IB first stage, a cluster of four Titan I first stages used for a second stage, a S-IV third stage and a Centaur high-energy liquid-fueled fourth stage.[2][3] Like its proposed predecessors, the Saturn B-1 never flew and neither did the Titan cluster stage. The S-IV however flew on the Saturn I.
^Bilstein, Roger E. (1996). Stages to Saturn: a technological history of the Apollo/Saturn launch vehicles. The NASA history series. Washington, DC: National Aeronautics and Space Administration, NASA History Office : For sale by the U.S. G.P.O., Supt. of Docs. ISBN978-0-16-048909-9.