Columbia subject headings:
Harvard subject headings:
Ackermans, Heinz--Art collections--Exhibitions.
Ackermans, Simone--Art collections--Exhibitions.
Art, Modern--20th century--Exhibitions
Art, Modern--Exhibitions
Boltanski, Christian, 1944-
Kunstsammlung Nordrhein-Westfalen (Germany)--Exhibitions.
Sammlung Ackermans--Exhibitions.
Princeton subject headings:
Art, Modern--20th century--Exhibitions.
Art, Modern--Germany--Düsseldorf--Exhibitions.
Boltanski, Christian, 1944-
Sammlung Ackermans--Exhibitions.