Chisholm, Roderick M.
Prentice Hall International, 1989
Buku Teks
Dicker, Georges
Oxford University Press , 2004
Buku Teks
Walker, Lorraine Olszewski
Appleton & Lange , 1988
Buku Teks
Walker, Lorraine Olszewski
Appleton & Lange, 1995
Buku Teks
Barnes, Barry
Routledge & K. Paul, 1974
Buku Teks