Bureau of International Information Programs United States Department of State, 2004
Buku Teks
Epps, Garrett, author
Oxford Univesity Press, 2013
Buku Teks
Westview Press, 1988
Buku Teks
Joy Hakim, author
Oxford University Press, 2003
Buku Teks
Trofimenko, Genrikh
Progress Publishers, 1986
Buku Teks