Columbia subject headings:
Labor unions--Terminology.
Working class--Terminology.
Working class--United States--Dictionaries.
Harvard subject headings:
Labor and laboring classes--Terminology.
Labor unions--Terminology.
Labor--Terminology.
Labor--United States--Dictionaries.
Working class--Terminology.
Working class--United States
Working class--United States--Dictionaries.
Princeton subject headings:
Labor movement--United States--Dictionaries.
Labor unions--United States--Dictionaries.