Columbia subject headings:
Harvard subject headings:
Clavichord--Congresses.
Clavichord--History--Congresses.
Hässler, Johann Wilhelm, 1747-1822--Thematic catalogs.
Princeton subject headings:
Clavichord music--History and criticism--Congresses.
Clavichord--Congresses.
Clavichord--History--Congresses.