Berges, Steve, author
American Management Association, 2006
eBooks
Koch, Edward T., author
Kencana Prenada Media Group, 2008
Buku Teks
Morris, Kenneth M., author
Lightbulb Press, 1998
Buku Referensi
ASEAN Secretariat, 1999
Buku Teks
edited by William Wels
Lippincott Williams & Wilkins, 2003
Buku Teks