Conversation so far:
where did Murray Rothbard go to school?
Murray attended Birch Wathen, a private school in New York City.
did he study anywhere else?
He attended Columbia University.
what did he study?
he received a Bachelor of Arts degree in mathematics in 1945 and, eleven years later, his PhD in economics in 1956.
did he do any research?
CANNOTANSWER.

Question: what did he do after his time in college?
Self-contained rewrite: What did Murray Rothbard do after his time in college?