1
Published 2003
2
3
by Shawcross, William
Published 1994
4
Published 1998
5
Published 2007
6
Published 2006
7
Published 1995
8
by Kotz, David M.
Published 2007
9
10
by Webber, Mark
Published 1996
11
by Kotler, Philip
Published 2007
12
Published 2003
13
by Premdas, Ralph R.
Published 1995
14
by Hughes, Caroline
Published 2003
15
Published 1998
16
Published 2003
17
Published 2000
18
19
Published 1996
20
by Ford, Glyn
Published 2008