Michael Milland, it looks like six people posted after you, and not one person noticed your goof. It was Oscar Hammerstein II who was the primary lyricist for Jerome Kern's music for "Old Man River" and all the other songs in the 1927 musical Show Boat. Beginning with Oklahoma! in 1943, Hammerstein wrote music for the music of Richard Rodgers, who had been teamed with Lorenz Hart. Don't think Rodgers wrote many lyrics, although he was a prolific composer.
-Joe Offer-