Columbia subject headings:
Factory inspection--Periodicals.
Labor bureaus--United States--Periodicals.
Labor laws and legislation--Periodicals.
Harvard subject headings:
Factory inspection--Canada--Congresses.
Factory inspection--United States--Congresses.
Labor bureaus--Canada--Congresses.
Labor bureaus--United States--Congresses.
Labor laws and legislation--Canada--Congresses.
Labor laws and legislation--United States--Congresses
Princeton subject headings: