Armstrong, Michael, author
Gramedia, 2003
Buku Teks
Twisk, Jos W.R., author
Cambridge University Press, 2006
Buku Teks
Drago, Carl, author
Blackwell Publishing, 2007
Buku Referensi
Ziegler, Kathleen, author
Rockport Publishers, 1994
Buku Referensi
Drago, Carl, author
Blackwell, 2014
Buku Teks