Columbia subject headings:
Documentary photography--History--20th century--Exhibitions.
Labor movement--History--20th century--Exhibitions.
Harvard subject headings:
Documentary photography--Exhibitions
Photography--Political aspects--History--20th century--Exhibitions.
Photography--Social aspects--History--20th century--Exhibitions.
Working class--Portraits--Exhibitions.
Princeton subject headings:
Documentary photography--History--20th century--Exhibitions.
Labor movement--History--20th century--Exhibitions.