Columbia subject headings:
Althoff, Friedrich, 1839-1908--Correspondence.
Mommsen, Theodor, 1817-1903--Correspondence.
Harvard subject headings:
Althoff, Friedrich, 1839-1908--Correspondence.
Mommsen, Theodor, 1817-1903. Correspondence.
Princeton subject headings:
Althoff, Friedrich, 1839-1908--Correspondence.
Mommsen, Theodor, 1817-1903. Correspondence.