Columbia subject headings:
Labor economics.
Labor supply--Great Britain.
Labor supply--United States.
Labor unions--Great Britain.
Labor unions--United States.
Harvard subject headings:
Labor economics.
Labor supply--Great Britain.
Labor supply--United States.
Labor unions--Great Britain
Labor unions--United States
Princeton subject headings:
Labor economics.
Labor supply--Great Britain.
Labor supply--United States.
Labor unions--Great Britain.
Labor unions--United States.