Columbia subject headings:
Beethoven, Ludwig van, 1770-1827. Fidelio (1814)--Congresses.
Women in opera--Congresses.
Harvard subject headings:
Beethoven, Ludwig van, 1770-1827. Fidelio (1814)--Congresses.
Women in literature--Congresses
Women in opera--Congresses.
Princeton subject headings:
Beethoven, Ludwig van, 1770-1827. Fidelio (1814)--Congresses.
Women in opera--Congresses.