Columbia subject headings:
Labor supply--Congresses.
Labor supply--United States--Congresses.
Migration, Internal--Congresses.
Migration, Internal--United States--Congresses.
Harvard subject headings:
Labor supply--Congresses.
Labor supply--United States--Congresses.
Migration, Internal--Congresses
Migration, Internal--United States--Congresses.
Princeton subject headings:
Labor supply--Congresses.
Labor supply--United States--Congresses.
Migration, Internal--Congresses.
Migration, Internal--United States--Congresses.