Young, Harold A.
Buckley Press, 1957
Buku Teks
Conway, Mary E., author
Appleton , 1983
Buku Teks
Redman, Barbara Klug, author
Mosby , 2007
Buku Teks
Knowles, Malcolm S., author
Cambridge University Press, 1980
Buku Teks
Angel M.y. Lin; Peter W. Martin
Buffalo : Multilingual Matters, 2005
Buku Teks