Columbia subject headings:
Labor unions--United States--Periodicals.
Labor--United States--Periodicals.
Working class--United States--Periodicals.
Harvard subject headings:
Labor unions--United States--Periodicals
Labor--United States--Periodicals
Working class--United States--Periodicals
Princeton subject headings:
Labor unions--United States--Periodicals.
Labor--United States--Periodicals.
Periodicals.
Working class--United States--Periodicals.