Columbia subject headings:
Art, German--Germany (West)--20th century--Exhibitions.
Piene, Otto, 1928-2014--Exhibitions.
Harvard subject headings:
Art, Modern--20th century--Exhibitions
Art, Modern--20th century--Germany (West)--Exhibitions.
Piene, Otto, 1928---Exhibitions.
Piene, Otto, 1928-2014--Exhibitions.
Princeton subject headings: