Columbia subject headings:
Austria--Politics and government--1867-1918.
Mayerling (Austria)
Princes--Austria--Biography.
Rudolf, Crown Prince of Austria, 1858-1889.
Harvard subject headings:
Austria--Politics and government--1867-1918.
Mayerling (Austria)
Princes--Austria--Biography
Rudolf, Crown Prince of Austria, 1858-1889
Princeton subject headings:
Rudolf, Crown Prince of Austria, 1858-1889.
Vetsera, Mary, Baronesse, 1871-1889.