Columbia subject headings:
Hodler, Ferdinand, 1853-1918--Exhibitions.
Sommer, Ferdinand, 1822-1901.
Harvard subject headings:
Hodler, Ferdinand, 1853-1918--Exhibitions.
Sommer, Ferdinand, 1822-1901--Exhibitions.
Princeton subject headings:
Hodler, Ferdinand, 1853-1918--Exhibitions.
Sommer, Ferdinand, 1822-1901--Exhibitions.