edited by Malcolm Warner
Business Press, 2000
Buku Referensi
Hirsch, Philip
The Jacaranda press, 1991
Buku Teks
Greenberg, Simon, author
Cambridge University Press, 2011
Buku Teks
Islam, Iyanatul, author
Routledge, 1997
Buku Teks
Routledge, 1999
Buku Teks