Ministry of Foreign Affairs, 1995
Buku Teks
Goodspeed, Stephen S., author
Oxford University Press, 1963
Buku Teks
Coyle, David Cushman, 1887-1969, author
Columbia University Press, 1963
Buku Teks
Gross, Ernest A.
Harper & Brothers, 1962
Buku Teks
United Nations Department of Public Information, 1989
Buku Teks