Arnold, part of the Hodder Headline group, 2018
Majalah, Jurnal, Buletin
Aldridge, W. Norman
Taylor and Francis, 1996
Buku Teks
edited by Bryan Ballantyne, Timothy Marrs and Paul Turner
Macmillan, 1995
Buku Teks
Springer, 2012
eBooks
edited by Ernest Hodgson
John Wiley & Sons, 2010
Buku Teks