Columbia subject headings:
Congress of Industrial Organizations (U.S.)
Labor unions and communism--United States--History.
Socialism--United States--History.
Harvard subject headings:
Congress of Industrial Organizations (U.S.)
Labor unions and communism--United States--History.
Socialism--United States--History
Princeton subject headings:
Congress of Industrial Organizations (U.S.)
Labor unions and communism--United States--History.
Socialism--United States--History.