Columbia subject headings:
Harvard subject headings:
Haller, Johannes, 1865-1947--Correspondence.
Historians--Germany--Correspondence
Intellectuals--Germany--Correspondence.
Organists--Germany--Correspondence.
Straube, Karl, 1873-1950--Correspondence.
Princeton subject headings:
Haller, Johannes, 1865-1947
Straube, Karl, 1873-1950