Grann, David, author
Gramedia Pustaka Utama, 2015
Buku Teks
Vegas, Annette, author
Springer, 2012
eBooks
Walliman, Nicholas, author
Sage Publications Ltd , 2001
Buku Teks
Feigin, Gerald, author
Business Expert Press, 2011
Buku Teks
Hawkins, Barrie, author
Piatkus, 1993
Buku Teks