Vernon-Wortzel, Heidi, author
John Wiley & Sons, 1997
Buku Teks
Bryson, George D.
Harper & Brothers, 1961
Buku Teks
Toyne, Brian
Allyn and Bacon, 1989
Buku Teks
Elashmawi, Farid, author
Gramedia Pustaka Utama, 1996
Buku Teks
International Development Research Centre and Institute of Southeast Asian Studies, 1997
Buku Teks