Columbia subject headings:
Berlinische Galerie--Exhibitions.
Groenke, Gisela--Art collections--Exhibitions.
Groenke, Klaus--Art collections--Exhibitions.
Rickey, George--Criticism and interpretation.
Rickey, George--Exhibitions.
Harvard subject headings:
Berlinische Galerie--Exhibitions.
Rickey, George--Exhibitions.
Princeton subject headings:
Berlinische Galerie--Exhibitions.
Rickey, George--Criticism and interpretation.
Rickey, George--Exhibitions.