Columbia subject headings:
Harvard subject headings:
Klein, H. G--Art collections.
Niederrheinisches Freilichtmuseum.
Toys--Private collections--Germany (West)--Grefrath (Viersen)
Princeton subject headings:
Art--Private collections--Germany (West)--Cologne--Catalogs.
Klein, H.G.--Art collections--Catalogs.
Niederrheinisches Freilichtmuseum--Catalogs.