Conversation so far:
Where did Murray Rothbard go to school?
Murray Rothbard attended Birch Wathen, a private school in New York City.
Did Murray Rothbard study anywhere else besides Birch Wathen?
Murray Rothbard attended Columbia University.
What did Murray Rothbard study at Columbia University?
Murray Rothbard received a Bachelor of Arts degree in mathematics in 1945 and eleven years later his PhD in economics in 1956.

Question: Did he do any research?
Self-contained rewrite: Did Murray Rothbard do any research?