Columbia subject headings:
Artists--Germany--Correspondence--Exhibitions.
Beckmann, Max, 1884-1950--Correspondence--Exhibitions.
Beckmann, Max, 1884-1950--Exhibitions.
Piper, Reinhard--Correspondence--Exhibitions.
Harvard subject headings:
Artists--Germany--Correspondence--Exhibitions.
Beckmann, Max, 1884-1950--Correspondence--Exhibitions.
Beckmann, Max, 1884-1950--Exhibitions.
Piper, Reinhard--Correspondence--Exhibitions.
Princeton subject headings: