Nahavandi, Afsaneh
Pearson/Prentice Hall, 2009
Buku Teks
Riehl-Sisca, Joan
Appleton-Century-Crofts, 1985
Buku Teks
Skeet, Muriel
Churchill Livingstone , 1980
Buku Teks
Nahavandi, Afsaneh
Prentice-Hall, 2000
Buku Teks
Asch, David
Crest Publishing House, 1999
Buku Referensi