Columbia subject headings:
Harvard subject headings:
Helbig, Ernst, 1802-1866--Catalogues raisonnés.
Helbig, Ernst, 1802-1866--Exhibitions.
Princeton subject headings:
Catalogs.
Catalogues raisonnés.
Helbig, Ernst, 1802-1866--Catalogues raisonnés.
Romanticism in art--Germany--Catalogs.