Case, Caroline
Routledge, 2005
Buku Teks
Bishop, Matt
Addison-Wesley, 2003
Buku Teks
Speser, Phyllis L.
John Wiley & Sons, 2006
Buku Teks
Lyman, Michael D.
Pearson/Prentice Hall, 2005
Buku Teks
Nahavandi, Afsaneh
Pearson/Prentice Hall, 2009
Buku Teks