Columbia subject headings:
Art, Modern--20th century--Exhibitions.
Marx, Erich--Art collections--Exhibitions.
Harvard subject headings:
Art, Modern--20th century--Exhibitions
Beuys, Joseph--Exhibitions.
Marx, Erich--Art collections--Exhibitions.
Rauschenberg, Robert, 1925---Exhibitions.
Twombly, Cy, 1928---Exhibitions.
Warhol, Andy, 1928-1987--Exhibitions.
Princeton subject headings:
Art, Modern--20th century--Exhibitions.
Marx, Erich--Art collections--Exhibitions.