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