Gregg, Pauline
George G. Harrap, 1967
Buku Teks
Lindberg, Jordan J.
Mayfield Publishing Company, 2001
Buku Teks
Nadeak, Carry
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