Lindberg, Jordan J., author
Mayfield Publishing Company, 2001
Buku Teks
Nadeak, Carry, author
Java Media Indo Plus, 2003
Buku Teks
Acton, Edward
Longman, 1986
Buku Teks
edited by Stephanie Abraham Hirsh and Philip Bacon
Harcourt Brace Jovanovich, 1988
Buku Teks
Wallbank, T. Walter, author
Scott, Foresman, 1965
Buku Teks