Garrett, Leonard C. , author
Author House, 2012
Buku Teks
Suaram Komunikasi, 2011
Buku Teks
Foster, Steve, author
Oxford university press, 2012
Buku Teks
Newman, Edwin S., author
Oceana Publications,Inc., 1979
Buku Teks
Selby, David, author
Cambridge University Press, 1988
Buku Teks