Columbia subject headings:
Art objects, European--Exhibitions.
Art--Collectors and collecting--Europe--Exhibitions.
Art--Private collections--Germany--North-Rhine Westphalia--Exhibitions.
Drawing, European--Exhibitions.
Painting, European--Exhibitions.
Harvard subject headings:
Art objects, European--Exhibitions.
Art--Private collections--Germany--North Rhine-Westphalia--Exhibitions.
Drawing, European--Exhibitions.
Painting, European--Exhibitions.
Princeton subject headings:
Art objects, European--Exhibitions.
Art--Collectors and collecting--Europe--Exhibitions.
Art--Private collections--Germany--North-Rhine Westphalia--Exhibitions.
Drawing, European--Exhibitions.
Painting, European--Exhibitions.