Lloyd, Elizabeth Jane, author
Simon & Schuster, 1990
Buku Referensi
Lloyd, Elizabeth Jane
New York: Simon ans Schuster, 1990,
Buku Referensi
Becker, Mortimer, 1920-, author
Prentice-Hall, 1949
Buku Teks
Sharpe, Gareth, author
Guinness Publishing, 1994
Buku Referensi
Sides, Dorothy Smith
Dover, 1961
Buku Teks