Conversation so far:
What did Yip Harburg do in Hollywood?
In Hollywood, Yip Harburg worked with composers Harold Arlen, Vernon Duke, Jerome Kern, Jule Styne, and Burton Lane, and later wrote the lyrics for The Wizard of Oz

Question: Did he work on this alone or with others?
Self-contained rewrite: Did Yip Harburg work on The Wizard of Oz alone or with others?