Potapova, Nina F., author
Progress Publishers, [196-]
Buku Teks
Katzner, Kenneth, author
John Wiley & Sons, 1994
Buku Referensi
Bennett, Jeffrey O.
Pearson - Addison Wesley, 2009
Multimedia
Verlinden, Jay, author
Wadsworth/Thomson Learning, 2005
Buku Teks
Cambridge University Press, 2004
Buku Teks