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Berghahn Books, 2006
Buku Teks
Sarabjot Singh
Management, Faculty of Economics, University of Indonesia and Philip Kotler Center, 2013
Artikel Jurnal
Damisch, Hubert
MIT Press, 2000
Buku Teks SO
Ruzaimi Mat Rani
Words & Visuals Press Pte Ltd,
Buku Referensi
Rachel Koh
Page one publishing pte ltd, 2010
Buku Teks SO