Columbia subject headings:
Harvard subject headings:
Knigge, Adolf, Freiherr von, 1752-1796--Correspondence.
Nicolai, Friedrich, 1733-1811--Correspondence.
Princeton subject headings:
Knigge, Adolf, Freiherr von, 1752-1796--Correspondence.
Nicolai, Friedrich, 1733-1811--Correspondence.