Murphy, Tom
American Management Association, 2007
eBooks
Kiki Syahnakri
Kompas Media Nusantara, 2013
Buku Teks
Siti Hawa Mohd., Datin Hjh
MPH Group Publishing Sdn Bhd, 2012
Buku Teks
Kiki Syahnakri
Kompas Media Nusantara, 2013
Buku Teks
Howe, Sean
HarperCollins, 2012
Buku Teks SO