Woodham, Jonatham M., author
Oxford University Press, 1997
Buku Teks
Carter, Gwendolen M., author
Praeger, 1973
Buku Teks
Ewen, David, author
Prentice Hall, 1968
Buku Referensi
Schaller, Michael, author
Oxford University press, 1979
Buku Teks
Kim, Young-na, author
Laurence King Publishin, 2005
Buku Teks