Columbia subject headings:
Harvard subject headings:
Concrete art--Europe--Exhibitions.
Galerie Schoeller--History.
Leopold-Hoesch-Museum der Stadt Düren--Exhibitions.
Schoeller, Hubertus--Art collections--Exhibitions.
Princeton subject headings:
Concrete art--Europe--Exhibitions.
Galerie Schoeller--History.
Leopold-Hoesch-Museum der Stadt Düren--Exhibitions.
Schoeller, Hubertus--Art collections--Exhibitions.