Columbia subject headings:
Catholic labor unions--United States--History--20th century.
Labor--Religious aspects--Christianity--United States--History--20th century.
Harvard subject headings:
Catholic labor unions--United States--History--20th century.
Labor--Religious aspects--Christianity--United States--History--20th century.
Labor--United States--Religious aspects--Christianity--History--20th century.
Princeton subject headings:
Catholic labor unions--United States--History--20th century.
Labor--Religious aspects--Christianity--United States--History--20th century.