Kinsella, Sophie
Jangan bilang-bilang ya... = can you keep a secret
Gramedia Pustaka Utama, 2003
 Buku Teks SO
Abeyratne, Ruwantissa
Asean single aviation market and indonesia - can it keep up with the giants?
Faculty of Law University of Indonesia, 2014
 Artikel Jurnal
Locke, A.
The tigers of Trengganu
The Malaysian Branch of the Royal Asiatic Society, 1993
 Buku Teks
Zemke, Ron
E-Service : 24 ways to keep your customers-when the competition is just a click away
Amacom, 2000
 Buku Teks SO
The stars and stripes story of World War II
edited by Robert Meyer
David McKay Company, 1960
 Buku Teks SO