Columbia subject headings:
Harvard subject headings:
Collective labor agreements--United States.
Industrial relations--United States
Labor unions--Law and legislation--United States
Open and closed shop--Law and legislation--United States.
Unfair labor practices--United States.
Princeton subject headings:
Collective labor agreements--United States.
Industrial relations--United States.
Labor unions--Law and legislation--United States.
Open and closed shop--Law and legislation--United States.
Unfair labor practices--United States.