Conversation so far:
Who was in a business partnership with John D. Rockefeller?
In 1859, John D. Rockefeller went into business with a partner, Maurice B. Clark.
What kind of business were John D. Rockefeller and Maurice B. Clark into?
John D. Rockefeller and Maurice Clark went into the produce commission business that transitioned oil refineries.

Question: what other partnership did he have?
Self-contained rewrite: What other business partnership besides Clark's did John D. Rockefeller have?