Columbia subject headings:
Rudolf, Crown Prince of Austria, 1858-1889.
Vetsera, Mary, Baronesse, 1871-1889.
Harvard subject headings:
Rudolf, Crown Prince of Austria, 1858-1889
Vetsera, Mary, Baronesse, 1871-1889.
Princeton subject headings:
Rudolf, Crown Prince of Austria, 1858-1889.
Vetsera, Mary, Baronesse, 1871-1889.