Columbia subject headings:
Beethoven, Ludwig van, 1770-1827.
Nägeli, Hans Georg, 1773-1836.
Harvard subject headings:
Beethoven, Ludwig van, 1770-1827
Nägeli, Hans Georg, 1773-1836.
Princeton subject headings:
Beethoven, Ludwig van, 1770-1827.
Musicians--Correspondence.
Nägeli, Hans Georg, 1773-1836.