Columbia subject headings:
Opera--Austria--Vienna--Chronology.
Wiener Staatsoper.
Harvard subject headings:
Opera--Austria--Vienna--20th century.
Opera--Austria--Vienna--21st century.
Wiener Staatsoper--Registers.
Princeton subject headings:
Opera--Austria--Vienna--20th century.
Opera--Austria--Vienna--21st century.
Wiener Staatsoper--History--20th century.
Wiener Staatsoper--History--21st century.