Australian.Department of Education
Australian Government Publishing Service, 1979
Buku Referensi
UNESCO, 1978
Buku Teks
Her Majesty's Stationery Office, 1987
Buku Teks
edited by Maria Slowey, David Watson
Open University Press, 2003
Buku Teks
Smith, Huston, author
Harper & Brothers, 1955
Buku Teks