Columbia subject headings:
Beethoven, Ludwig van, 1770-1827.
Beethoven, Ludwig van, 1770-1827. Operas.
Harvard subject headings:
Beethoven, Ludwig van, 1770-1827
Beethoven, Ludwig van, 1770-1827. Operas.
Princeton subject headings:
Beethoven, Ludwig van, 1770-1827.
Beethoven, Ludwig van, 1770-1827. Operas.