edited by Theodore L. Becker and Vernon G. Murray
Oxford University Press, 1971
Buku Teks
Bailey, Stephen K., author
Henry Holt, 1957
Buku Teks
Adams, Walter, 1922-1998, author
Macmillan, 1957
Buku Teks
Seckler-Hudson, Catheryn, author
United State Information Service, 1959
Buku Teks
The America University, [date of publication not identified]
Buku Teks