Columbia subject headings:
Harvard subject headings:
Blümel, Otto, 1881-1973--Friends and associates--Exhibitions.
Hesse, Hermann, 1877-1962--Friends and associates--Exhibitions.
Princeton subject headings:
Blümel, Otto, 1881-1973--Friends and associates--Exhibitions.
Hesse, Hermann, 1877-1962--Friends and associates--Exhibitions.