Columbia subject headings:
Harvard subject headings:
German language--Dialects--Silesia--History--Congresses.
German language--Middle High German, 1050-1500--History--Congresses.
German language--Silesia--History--Congresses.
Princeton subject headings:
German language--Germany--Schleswig-Holstein--History--Congresses.
German language--History--Congresses.
German language--Middle High German, 1050-1500--History--Congresses.