Columbia subject headings:
Harvard subject headings:
Droysen, Johann Gustav, 1808-1884--Congresses.
Droysen, Johann Gustav, 1808-1884--Criticism and interpretation--Congresses.
Historians--Germany--Congresses.
Historiography--Congresses
Historiography--Germany--History--19th century--Congresses.
Princeton subject headings:
Droysen, Johann Gustav, 1808-1884--Congresses.
Historians--Germany--Congresses.
Historiography--Germany--History--19th century--Congresses.