Columbia subject headings:
Germany--History--Revolution, 1848-1849--Sources.
Labor unions--Germany--Congresses--History--19th century--Sources.
Labor unions--Germany--History--19th century--Sources.
Working class--Germany--Congresses--History--19th century--Sources.
Working class--Germany--History--19th century--Sources.
Harvard subject headings:
Germany--History--Revolution, 1848-1849--Sources.
Labor unions--Germany--Congresses--History--19th century--Sources.
Labor unions--Germany--History--19th century--Sources.
Working class--Germany--Congresses--History--19th century--Sources.
Working class--Germany--History--19th century--Sources.
Princeton subject headings: